How to graph a horizontal parabola by completing the square first (mistake)
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- Опубліковано 6 лют 2025
- Learn how to graph a horizontal parabola. A parabola is the shape of the graph of a quadratic equation. A parabola is said to be horizontal if it opens to the left or opens to the right. A horizontal parabola results from a quadratic equation in which the y part of the equation is squared.
To sketch the graph of a parabola, we first identify the vertex, the focus and the directrix. To do this, we first using completing the square method to write the equation in the form (y - k)^2 = 4p(x - h), where (h, k) is the vertex and p is the distance between the vertex and the focus.
After expressing the equation in the form (y - k)^2 = 4p(x - h), the vertex is given by (h, k), the focus is given by (h + p, k) and the directrix is given by the line x = h - p. After obtaining the vertex, the focus and the directrix, we can then sketch the parabola.
#conicsections #parabolaconicsections
How come that -2-2=0 if you are going to change it, it becomes like this: -2+(-2)= -4. Please enlighten me how it became 0.
it is -4 my mistake. Thank you for point out
it is zero because directrix is x= h-p , (P) =-2 thus canceling out x= - 2 -(-2) which makes x=0
yeah! your right
he wrote -2- -2 there but not clear but he said it correct. listen to him carefully
@@brianmclogan 0 is the right answer because if the answer is negative your directrix woul lie inside your parabola
Why couldn't all teachers be like you? You have so much patience, knowledge, and a sense of humor. We need more Brian McLogans in the world.
I hope you're doing good, sir! You're reall helping me with my Pre-Cal. Thank you!!
your the real goat saving all of us from F's
Best teacher
Excellent class
i love you teacher
How did you get the 2?
Its really great but I am getting confused to decide whether its left or right
Thanks! It us really useful.
In the event that you are required to plot the parabola accurately, how do you determine the arc of the parabola? More specifically, the exact points it should pass through?
best bet is to choose values for y and plug them in to determine the values of x. Then plot those points, if it was a vertical parabola you would choose values for x to determine the y
Thanks for replying! So, I've done that but on more than one occasion, I get decimals/fractions/roots or numbers that are obnoxious to graph. Is there any easier way to do it?
it depends on the equation, some will be very nice and others not so nice, in this example picking points is not that nice, there is some tips but honestly I don't feel it is worth that much of your time, pick two points, including the vertex and that should be enough for a "sketch" If you want accuracy use a calculator
Okay, thank you! Your videos are unbelievably helpful. Whatever you do, don't stop publishing!!!
Thank you, this really helped
awesome! happy to be able to help
Thanks sir you are awesome.and i am from india.
awesome! happy to help
What is your basis for choosing the standard equation?
It should be -6y?how did you get negative 6...Then your another video in finding x is in positive
I’m wondering where is your solution for finding the latus rectum?
I do not cover it much in my videos but it is just 4p
Why the parabola opens to the left??🛑
Thank you Sir
you are very welcome!
hello sir, how did you factor out -8? thank you
think of factoring out -8 as dividing out -8 or dividing both terms by -8
@@brianmclogan thank you!
you are very welcome!
Ms. Blanco Brought me here who else?
xD me
I was forced... aaahahaha joke
meeee! 👋
egg
count me in!
Sir, can you help me with this
y^2 - 6x + 6y + 17 = 0
I tried to solve this but when it comes in identifying the k here i don't know how to make it as a whole number. Because when i'm already done at making a perfect trinomial, i put it in both sides, but the answer is in fraction form. I'm so confused, I don't know how to get the value of k huhuhu
sorry only able to focus on what I am currently teaching but yes the process is the same as this video
Sir please help me with this
What about if a is 3?
3y²+4x-24y+44=0
I think you need to multiply both sides by 1/3 in order to eliminate the 3 after factoring the 3y raised to the power of 2 -8
@@aelenposadas5146 Thanks
x=h-p
p= -2
h= -2
So,
x= -2-(-2)
x= -2+2
x=0
I'm really confused
that is correct
can you help me with this??? x^2+x-6=0 pls
(x+2)(x-2)=0 now use zero product property to solve
what about x^2+4y^2=16?
divide by 16 on both sides so the equation is equal to one. then you can graph. Here are more examples
ua-cam.com/play/PL0G-Nd0V5ZMrfjT_QryhU2-sqC0WmKJQN.html
find the vertex ,focus,directrix, latus rectum and axis of the parabola 4y^2+12x--12y+39=0 plz sir, solve this question.
+Bullet storm sorry, I only time to work out problems for videos for my students. I have many videos similar to that problem
-2-2=0 not -4???
gemarlo lasala think about it this way. You owe me two dollars(-2) you borrow two more dollars from me (-2). You now owe me for dollars (-4). Does that help?