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Integration help!

I'm quite stuck on this

1
______________ dx

(1-x^2)^1.5)

Substitution is x=sinθ and the limits given are 0.5 and 0

any help/advice would be appreciated!
Original post by The Hedonist
I'm quite stuck on this

1
______________ dx

(1-x^2)^1.5)

Substitution is x=sinθ and the limits given are 0.5 and 0

any help/advice would be appreciated!


1/(cos^2theta)^1.5 go from there . Also remember to change the limits.
(edited 12 years ago)
Reply 2
Well what have you tried? Certainly that substitution looks like a good idea.
Reply 3
Original post by Deep456
1/(cos^2theta)^1.5 go from there . Also remember to change the limits.


but surely:

dxdθ=cosθ\frac{dx}{d\theta} = cos\theta so dx=cosθdθ dx = cos\theta d\theta

so the integral would be
Unparseable latex formula:

\frac {cos\theta}{(cos^2\theta)^1^.^5} d\theta

(edited 12 years ago)
Original post by just george
but surely:

dx/dtheta = cos(theta) so dx = cos(theta) dtheta

so the integral would be cos(theta) / (cos^2theta)^1.5 dtheta


All I have done is subbed in sin theta and used the identity. I haven't done anything else.

What you have done is also correct ,yes.
(edited 12 years ago)
Reply 5
Original post by Deep456
All I have done is subbed in sin theta and used the identity. I haven't done anything else.


sorry yeah it just looked a bit misleading to me, looked like you were saying the integral was
Unparseable latex formula:

\frac{1}{(cos^2\theta)^1^.^5}

:smile:

The Hedonist - basically just use the substitution given, remember to change between dx and dtheta, the limits, and then hopefully you will be left with something you can integrate :smile:
(edited 12 years ago)

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