Question

If f(x)=8arcsin(x2), find the derivative.
Help me please! Thanks so much!

Answer 1

integral number [18] in the back of my book says\[[18]\qquad\int\frac{\text d x}{\sqrt{a^2-x^2}}=\arcsin\left(\frac xa\right)+c\]

Answer 2

@donnac10 can you follow the formula?

Answer 3

Yeah.. I'm trying to see if I get the right answer. :)

Answer 4

Wait.. I'm kinda confuse now.. >_< Cause I see integral and I'm looking for a derivative.. >_<

Answer 5

( arcsin u ) = u' / sqrt ( 1 - u )

Answer 6

u = x^2
u' = ...

Answer 7

@donnac10 WHERE ARE YOU?

Answer 8

I'm sorry I was trying it out.. >_<

Answer 9

Can you take ( x^2) ' = ?

Answer 10

yeah.. It's 2x right?!?

Answer 11

Yup, pls just plug u and u' into the formula!

Answer 12

( arcsin u )' = u' / sqrt ( 1 - u )

Answer 13

@donnac10 Can you?

Answer 14

Yes, thanks so much for your help! Greatly appreciated! :D

Answer 15

@Chlorophyll I have another question. Sorry for asking too much.. >_< So what happens to the 8 in front of it?!?

Answer 16

It's the constant, keep it !

Answer 17

= 16x / sqrt ( 1 - x^2 )

Answer 18

Cause that's what I put on this homework website that I have been working on and it says it's wrong.. -_-

Answer 19

Put it here!

Answer 20

Which one?!?

Answer 21

The one you say wrong, so I can see why

Answer 22

Isn't it the 16x / sqrt ( 1 - x^2 )?!?

Answer 23

Try it: 16x / sqrt ( 1 - x^4 )

Answer 24

It's right! How did you do that?!?

Answer 25

I'm sorry that I typo in the formula
( arcsin u ) = u' / sqrt ( 1 - u ^2 )

Answer 26

u = x^2
=> u^2 = (x^2) ^2 = x^4

Answer 27

That's what I though.. I missed that! And I have been doing it for days.. Haha! Thanks so much for pointing that out! You're very helpful.. :D

Answer 28

That's the whole reason we need the asker show up :)

Answer 29

Pls, not to be annoyed if I keep calling out your name ;)

Answer 30

Thanks so much! Oh no.. It's actually quite helpful because I actually see that I have a notification.. Cause when people just reply I don't really see it.. >_< Thanks for being so patient!

Answer 31

That's how annoyed aggressive I am. Thanks for keep up with my temper ;)

Answer 32

Ohh really?!? It's cool... I think I work better when people are like that to me.. :P I'm like that too when I teach people.. So I totally understand.. :D