# Math Help - Check real fast please =)

1. ## Check real fast please =)

Find the derivative of the function.

y=x*cos^(-1)(x) - sqrt(1-x^2)

y'=cos^(-1)(x) + x(-1/sqrt(1-x^2)) + 2x/2(sqrt(1-x^2))

y'= cos^(-1)(x)

i think i did it right but it just seemed weird to me that it would reduce so much so i just wanted to make sure it is right haha

thank you

2. Hi

Could you make more specific wich is the argument of the $\cos$ function?

3. Originally Posted by mybrohshi5
Find the derivative of the function.

y=x*cos^(-1)(x) - sqrt(1-x^2)

y'=cos^(-1)(x) + x(-1/sqrt(1-x^2)) + 2x/2(sqrt(1-x^2))

y'= cos^(-1)(x)

i think i did it right but it just seemed weird to me that it would reduce so much so i just wanted to make sure it is right haha

thank you

that's correct

4. Originally Posted by mybrohshi5
Find the derivative of the function.

y=x*cos^(-1)(x) - sqrt(1-x^2)

y'=cos^(-1)(x) + x(-1/sqrt(1-x^2)) + 2x/2(sqrt(1-x^2))

y'= cos^(-1)(x)

i think i did it right but it just seemed weird to me that it would reduce so much so i just wanted to make sure it is right haha

thank you
It looks correct to me. When you add the last two terms together, they cancel.

5. ## correct!

Correct!
Here is a useful site/program to help with checking derivative and integrals, and lots of other usefull stuff:
- Wolfram|Alpha

6. Originally Posted by snaes
Correct!
Here is a useful site/program to help with checking derivative and integrals, and lots of other usefull stuff:
- Wolfram|Alpha
Wow that site is amazing. i cant believe how fast and accurate it is. that thing is amazing lol. will definitely come in handy when i study for my exam on tuesday.

thanks you so much again

7. Glad you like it!