Small Angle Approximations

A Level Maths revision tutorial video.
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[@possiblyunmatched1323]

For part b), why do you only use 1 value? How do you know whether to use tan or cos for the second example?

[@possiblyunmatched1323]

nvm. we want the value of x.

[@ReblazeGaming]

@@possiblyunmatched1323 could you explain pls?

[@AmanSingh-ck1lr]

@@ReblazeGaming the value 0.3 is 2x, x is 0.15

[@-ameera-9103]

@@AmanSingh-ck1lrohhh thank u sm i was so confused

[@pyroflame5414]

why do you only use cos 5 degrees in the 2nd example

[@jasoncheng7964]

also the equations r times theta, and 1/2 times rsquared theta only work for radians too

[@farhanhussain5712]

wdym

[@user-gd8td9kg3i]

Didn't understand part b) , how can you use the equation found in a) ? also, why only use 0.15 for x when there are 2 possible values right?

[@oliverhandforth2639]

Pretty Much SIn X = X so 0.15 is X Cos X cant be it as Cos X = 1 - x/2

[@jasoncheng7964]

no the inteval isnt specified so we dont have to find both values for x and abviously no 360 repeats, otherwise it would be much harder

[@foliagesw4736]

at 6:26 with question b why do you use 0.15 but not 0.3?

[@oliverhandforth2639]

Pretty Much SIn X = X so 0.15 is X Cos X cant be it as Cos X = 1 - x/2

[@hassanqais7996]

@@oliverhandforth2639 but in the next example he uses the cos value instead of the tan...
If you look in the qs, it's cos2x and sinx... So I suppose that cos x=0.15 as cos2x=0.3

[@helloandthanks9154]

2x = 0.3
x = 0.15

[@abbawada2954]

@@hassanqais7996 yeah for the second example the theta should've been 10 degrees idk why he used 5 because tan x = x

[@t_t725]

@@abbawada2954 but in the 2nd example tanx wasn't tanx it was tan2x so he used cosx