Calculus 1 Lecture 3.3: The First Derivative Test for Increasing and Decreasing

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  • Опубліковано 8 лют 2025
  • Calculus 1 Lecture 3.3: The First Derivative Test for Increasing and Decreasing of Functions

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  • @eliasrodriguez5054
    @eliasrodriguez5054 2 роки тому +53

    Man is both mentally and physically strong. That's someone to look up to. Great lesson and explanation

  • @Rahgnar2006
    @Rahgnar2006 11 років тому +69

    "no.. oh no, I'd burn your paper for that... hand ya back a staple!"
    This dude is too much hahaha

  • @educatedish2595
    @educatedish2595 8 років тому +118

    This guys amazing. Wherever he is teaching, they better be paying him good !

  • @jermainewells8506
    @jermainewells8506 3 роки тому +24

    I can't even begin telling you how these videos turned Calculus 1 around for me. My first test was a 60 which was the wake up call. Since then I've found these videos and haven't scored below a 90 on each exam.

  • @nikkim.2042
    @nikkim.2042 8 років тому +30

    This was so helpful. Thank you! My prof just rushes through things, never explains what or why he does things and just assumes we know how to simplify EVERYTHING. I wish he was this clear!

  • @funmaster5249
    @funmaster5249 5 років тому +23

    I think the most impressive thing here is how he memorized the mirrored function and uses those hand gestures to make it more clear for the students. If you think about it from his side its really impressive how hes so fluid with it. He has to flip the y axis on any graph he uses a hand gesture for.

  • @nicolevafiadis885
    @nicolevafiadis885 5 років тому +16

    Professor Leonard is really out here doing God's work

  • @angelinacabrera5576
    @angelinacabrera5576 8 років тому +74

    I shall quit physical school and just watch Superman's videos. I hate math righ now, but when I understand it I love it. LOVE HATE relationship. Cal1 is not my friend and neither is cal 2, 3 and dif Q. I look forward to taking those classes -______-

  • @SimplyGrouchy
    @SimplyGrouchy 9 років тому +80

    Wish my professor was this clear helped a lot thanks

    • @turkishgorilla2651
      @turkishgorilla2651 9 років тому

      +SimplyGrouch Same

    • @SlazeM7
      @SlazeM7 4 роки тому +1

      Stop being a weeb, things will become much clearer.

    • @fratakkaya667
      @fratakkaya667 3 роки тому

      @@SlazeM7 HAHAHAHAHAHAHAA

  • @michaelclendenon2921
    @michaelclendenon2921 8 років тому +9

    Thank you for going the extra step and posting these videos. I really appreciate your style and approach, it is very refreshing.
    Best of luck
    Casey

  • @shadabzahra6274
    @shadabzahra6274 4 роки тому +5

    I wish you were my actual teacher but still I am thankful to god to have access to this

  • @omarmorales3828
    @omarmorales3828 8 років тому +6

    This awesome. Teaches better than my actual professor. Thanks

  • @iñigote
    @iñigote Місяць тому +1

    ### Calculus 1 Lesson 3.3: The First Derivative Test for Increasing and Decreasing Functions
    Introduction
    ● [0:00] Professor Leonard introduces the topic: the first derivative test to determine intervals of increase and decrease of a function.
    ○ Mention of the application of this concept in curve sketching and understanding the shape of curves.
    Review of Previous Concepts
    ● [0:55] Review of the meaning of the first derivative and its relationship with a function’s increase and decrease.
    ○ [1:10] If 𝒇'(x) > 0, the function 𝒇(x) is increasing.
    ○ [2:16] If 𝒇'(x) < 0, the function 𝒇(x) is decreasing.
    ○ [2:33] If 𝒇'(x) = 0, the function 𝒇(x) has a horizontal tangent, and a critical number is identified.
    The First Derivative Test
    ● [3:05] Introduction to the first derivative test to find relative extrema (maximums and minimums).
    ● [3:26] Step-by-step explanation of the first derivative test:
    ○ 1.[4:21] Find the first derivative, 𝒇'(x).
    ○ 2.[4:40] Set the first derivative equal to zero, 𝒇'(x) = 0, to find critical numbers.
    ■ Besides the values where 𝒇'(x) = 0, the following points should also be included as “critical numbers,” where 𝒇'(x) does not exist:
    ◆ Points where the denominator is zero (possible vertical asymptotes).
    ► Occurs when the function is not defined (or tends to ±∞) as x approaches a certain value x = a.
    An example is 𝒇(x) = 1/x. As x approaches 0, 𝒇(x) tends to ±∞, and the line x = 0 is a vertical
    asymptote. Here, the function does not even reach a finite value at x = 0; it simply blows up to
    infinity (or negative infinity).
    ◆ Sharp corners or cusps (abrupt changes in slope).
    ◆ Vertical tangents (infinite slope).
    ► Occurs when the function is (or can be) defined at that point, but its slope (derivative)
    becomes infinite (or tends to ±∞). A typical example is 𝒇(x) = x^(1/3) at x = 0. The function
    is indeed defined at x = 0, but its derivative 𝒇'(x) = 1 / (3x^(2/3)) tends to ±∞ as x approaches 0,
    indicating a vertical tangent.
    ◆ Discontinuities (jump, infinite, removable).
    ○ 3. [4:58] Create a first derivative chart with critical numbers in order.
    ■ Draw a number line and mark the critical numbers.
    ■ Place 𝒇'(x) above the number line.
    ○ 4. [6:16] Test a point in each interval defined by the critical numbers.
    ■ Determine the sign of 𝒇'(x) in each interval.
    ◆ Substitute a value from each interval into 𝒇'(x) to determine if the slope is positive or negative.
    ■ The sign of 𝒇'(x) indicates whether the function is increasing or decreasing in each interval.
    ◆ Local Maximum:
    ► If 𝒇'(x) changes from positive to negative at a critical number, there is a local maximum.
    ◆ Local Minimum:
    ► If 𝒇'(x) changes from negative to positive at a critical number, there is a local minimum.
    ◆ Neither Maximum nor Minimum:
    ► If 𝒇'(x) does not change sign at a critical number, it is not classified as a maximum or minimum.
    △ Sometimes referred to as a "horizontal inflection point" if:
    ▢ 𝒇'(x) = 0.
    ▢ The concavity changes (related to the second derivative).
    Example 1: 𝒇(x) = x³ -3x +1
    ● [10:44] Application of the first derivative test to an example.
    ○ Find the derivative of the function.
    ○ Factor the derivative to find critical numbers.
    ○ Check for values that make the derivative undefined (denominators).
    ○ Create a first derivative chart with critical numbers.
    ○ Test a value from each interval in 𝒇'(x) to determine the sign.
    ○ Interpret the results to determine intervals of increase and decrease.
    ○ [14:13] Identify relative extrema (maximums and minimums).
    ○ Find the points of the relative extrema by substituting x-values into the original function.
    Example 2: 𝒇(x) = 3x^(5/3) - 15x^(2/3)
    ● [17:12] Presentation of a second example to apply the first derivative test.
    ○ Find the first derivative of the function.
    ○ Factor the derivative to find critical numbers.
    ○ Check for values that make the derivative undefined (denominators).
    ○ Include values that make the denominator zero in the first derivative chart.
    ○ Create the first derivative chart with critical numbers, including values that make the denominator zero.
    ○ Test a value from each interval in 𝒇'(x) to determine the sign.
    ○ [23:05] Interpret the results to determine intervals of increase and decrease.
    ○ Identify relative extrema (maximums and minimums), considering values that make the denominator zero.
    ○ Determine whether the relative extrema are maximums or minimums.

  • @umangsaini8559
    @umangsaini8559 Рік тому +3

    Nobody talking abt Prof.'s humour👑

  • @santiagogarcia8748
    @santiagogarcia8748 6 років тому +6

    your videos are very straight forward . thank you for sharing the videos .

  • @hallandouvte4778
    @hallandouvte4778 4 роки тому +3

    He's simply the best.

  • @OMAR8635
    @OMAR8635 9 років тому +4

    Super helpful for my Ap Calc class, thanks

  • @dario3334
    @dario3334 7 років тому +3

    thank you for uploading these videos they help a lot

  • @sameterdogan1820
    @sameterdogan1820 5 років тому +3

    Hor thing and lesson was good :)Thanks superprofessor

  • @bernadetteg.tharngan4041
    @bernadetteg.tharngan4041 6 років тому +4

    wish I found this professor earlier. My current one is just making calculus way more complicated than this.

  • @SFYN..
    @SFYN.. 5 років тому +19

    1:15 I'll burn your paper and hand you back the staple... LOL

  • @DanT-iu6oc
    @DanT-iu6oc 5 років тому +1

    this man is a goddamn american hero

  • @notdead5458
    @notdead5458 7 років тому +2

    THANK YOU PROFESSOR!

  • @awashaaalkaabi2334
    @awashaaalkaabi2334 7 років тому +1

    ممتاز هالدكتور

  • @mazan7824
    @mazan7824 8 років тому +2

    so great!

  • @garfyy427
    @garfyy427 6 років тому +1

    It's lucky for not having to take this test in the class :D

  • @elanurerdogan8586
    @elanurerdogan8586 2 роки тому +1

    thank youuu

  • @johnlivingston6986
    @johnlivingston6986 Рік тому +1

    Professor Leonard drop the workout split

  • @NormaNsNs
    @NormaNsNs 7 років тому +2

    i took x^(2/3) as a factor and come up with the same answer on 18:33

  • @Omair-d3g
    @Omair-d3g 9 місяців тому +2

    I wish my teacher was also jacked maybe i would have focused more

  • @nishagc9753
    @nishagc9753 9 років тому +2

    hey, i wanted u to do deltan and epsilon form limit defination,
    please

  • @masterofmath449
    @masterofmath449 8 років тому +2

    @ 9:23 Professor why are you flipping me off? lol

  • @javanshirazizov1991
    @javanshirazizov1991 5 років тому +1

    at 4:21 function must be continuous at critical points (where f' is zero or not defined). Your rule is true only for differentiable functions. You restrict the class of functions.

    • @nicatismaylov4054
      @nicatismaylov4054 5 років тому +2

      If a function is differentiable, the function MUST be continuous. Existing critical points means that the function has a derivative or is differentiable. Eventually, you are not true.

  • @jacobm7026
    @jacobm7026 6 років тому +4

    Starting around 17 minutes...I have a problem with him assigning a positive value to points with negative values under a radical. Seems like positive/imaginary for anything less than 0

    • @actuary32174
      @actuary32174 4 роки тому

      This concerns me too. I agree with your point.

    • @moratasa9741
      @moratasa9741 4 роки тому +4

      @@actuary32174 idk if I misunderstood you or not but if you mean the radical in the second question its odd radical so it's legal to put negatives there

    • @heet69690
      @heet69690 Рік тому

      ​@@moratasa9741ah that makes sense. Thanks

    • @drw3043
      @drw3043 10 місяців тому

      Try substituting -8. It's a cubed root not a square root, so the cubed root of -8 is -2. (Check that (-2)^3=-8). When you plug -8 into the numerator, you also get a negative answer. A negative numerator and a negative denominator give a positive final answer.

  • @richardassal7788
    @richardassal7788 Рік тому +1

    for the function f(x) = 3x^(5/3) - 5x^(2/3): We determined in your video that the slope is undefined at x=0. However the original function is continuous at x=0. What does this mean?

    • @drw3043
      @drw3043 10 місяців тому

      If you look at the graph of the function, you can see that the slope is becoming vertical as we approach a sharp turn at x=0 . The slope of a vertical line is undefined, so that is why the first derivative is undefined at x=0 even though the function is continuous there. (The sharp turn also makes the derivative not exist at that point, this function just happens to have both a sharp turn and a vertical slope at the same point)

  • @spurti
    @spurti 2 роки тому +1

    But at 22:39 cube Root of x should not be equal to zero.

  • @cate9541
    @cate9541 5 місяців тому

    My goat

  • @cooltier6174
    @cooltier6174 4 роки тому +2

    @21:42 if x = 0 doesn’t it mean that graph has a vertical tangent ?

    • @moratasa9741
      @moratasa9741 4 роки тому

      yes and it can also possibly change signs (slope from decreasing to increasing and vise versa) there

  • @frankruscil680
    @frankruscil680 10 років тому +1

    How did you get the x^-1/3? How would 5^-1/3 * x = 5^2/3s?

    • @caseythefalcon81
      @caseythefalcon81 10 років тому +3

      Because x has an exponent of 1 therefore when factored it would be 1+-1/3=2/3 leaving it with 5^2/3

  • @binoschebarrett
    @binoschebarrett 9 років тому +4

    how did you pull out X ^-1/3 from X^2/3 and are left with an x?

    • @roadtoad3484
      @roadtoad3484 7 років тому

      Thank you! that really helped.

  • @Jasonasked1233
    @Jasonasked1233 2 роки тому +1

    How can f(x) = 3x^(5/3) - 15x^(2/3) be a function when it has sharp turns at f(0?

    • @drw3043
      @drw3043 10 місяців тому +2

      Functions are allowed to have sharp turns. The absolute value function f(x)=|x| is another example of a function that has a sharp turn at x=0. For the function in the lecture, there is a sharp turn at x=0 but the function is still continuous there. However if you look at the graph you can see that the slope gets steeper and steeper as we approach x=0. The slope becomes vertical, and the slope of a vertical line is undefined. Further, the slope is approaching positive infinity as we approach x=0 from the left, and the slope approaches negative infinity as we approach from the right. So even though the function is continuous at x=0, we see that the first derivative is undefined there so the function is not differentiable at x=0. That doesn't stop us from finding the derivative at the other points where it is defined.

  • @instaminox
    @instaminox 9 років тому +2

    here where Algebra is crutia and will not play with u! it you miss your critical numbers your answer will be in a critical condition and you will find yourself trying to catch up some points at the hospitals problems :D

  • @vennenmin123
    @vennenmin123 8 років тому

    f(x)=4x+2/2x-3 (4x plus 2, over 2x minus 3). The (1st derivatives) f'(x)= -16/(2x-3)^2 (negative 16 over 2x minus 3 raise to the power of 2), and the f"(x)= 64/(2x-3)^3 When ask when is f'(x) is increasing or decreasing. How to compute when the numerator has no x value). In (second derivatives) f"(x), how to compute when f(x) is positive(conveks) or when it is negative (concave)? Can someone at least explain the logic behind it? Eventually youtube link if there is any.

  • @marlinheck
    @marlinheck 6 років тому

    May I have the ISBN code for the calc text you are using.

  • @perezje23
    @perezje23 9 років тому

    Stupid question but is this the explanation for section 3.3 James Stewart 8th edition "how derivatives affect the slope of the graph"

  • @farhasyeda6799
    @farhasyeda6799 5 років тому

    2 to 3

  • @daphneblake4161
    @daphneblake4161 5 років тому

    Are these videos for first year university calculus?

    • @Peter_1986
      @Peter_1986 4 роки тому

      I think so, yes.
      I studied pretty much this exact content when I studied "Differential Calculus" on my first year in Engineering Physics.
      Then my final math course that year was "Multivariable Calculus", which is basically Calculus 3.

  • @TuanNguyen-yu7he
    @TuanNguyen-yu7he 9 років тому +1

    what edition is this Prof. Leonard? because i have edition 10th in my calculus and the chapters are different

  • @ayeshaarslan1381
    @ayeshaarslan1381 Рік тому +2

    bro why's that one kid always coughing in the back

  • @EldenEngineer
    @EldenEngineer 2 роки тому +1

    My fiancee also hates math.

  • @bigoshbomber
    @bigoshbomber 5 років тому +1

    I would die for you

  • @c1aniel
    @c1aniel 5 років тому +1

    my math teacher should kiss your shoes

  • @bateristicalan
    @bateristicalan 8 років тому

    16:10 am i the only one heard the fly?

  • @جميلة-ك4ط
    @جميلة-ك4ط 5 років тому +2

    ينطي واهس يقرا 😂

  • @greenmask487
    @greenmask487 2 роки тому +3

    Bro forget the calculus how can I have his physique 💀

  • @yonkamacho9842
    @yonkamacho9842 6 років тому +3

    He dabs at 24:37

  • @The_Angry_BeEconomist
    @The_Angry_BeEconomist 9 років тому +1

    lol @ how to find hors

  • @miraaziz5483
    @miraaziz5483 6 років тому

    lolllll

  • @mathsguy-ul8nj
    @mathsguy-ul8nj Рік тому +1

    bruh wear a full shirt, your biceps are too distracting(in a good way(like a compliment, but like, bad for me))