- #1
FallingMan
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Homework Statement
Integral (11x^2)/(25-x^2)^(3/2) dx from 0 to (5*sqrt(3))/2
Homework Equations
sin^2(θ) = 1 - cos^2(θ)
The Attempt at a Solution
1. Factor out 11 from integral for simplicity.
11 * integral (x^2)/(25-x^2)^(3/2)
2. Re-write denominator of integral to look similar to 1-cos^2(θ)
11 * integral (x^2)/(25(1-(1/25)x^2)))^(3/2)dx
3. Equate cos^2(θ) and (1/25)x^2
cos(θ) = (1/5)x
θ = arccos(1/5*x)
x = 5cos(θ)
dx = -5sin(θ)dθ
4. Substitute cos^2(θ) = (1/25)x^2 into integral, Substitute -5sin(θ)dθ = dx
11*(-5) * integral (x^2)(sin(θ)/(25(1-cos^2(θ)))^(3/2)
5. Substitute sin^2 for (1-cos^2)
-55 * integral (x^2)(sin(θ)/(25(sin^2(θ))^(3/2)
No idea what to do from here.
I have a feeling my approach in general is totally off. Any advice would be greatly appreciated.