Posted by **Vicky** on Thursday, September 20, 2012 at 1:42am.

Use the table of integrals to find int cos^4 3x dx

I found the table: ∫cos^n u du = (1/n)cos^(n-1)u sinu + (n-1/n)∫sin^(n-2)u du = 1/4 cos^(4-1)u sinu + (4-1/4)∫sin^(4-2) u du

so what i did the problem: let u=3x then du=3dx

=1/4*1/3 cos^3u sinu + 3/4*1/3 ∫sin^2 u du.

=1/12 cos^3u sinu + 1/4 -cos^2 u +c..

so am i doing right step??

## Answer This Question

## Related Questions

- calculus II - ∫ tan^2 x sec^3 x dx If the power of the secant n is odd, ...
- Calculus - Integrate 1/sinx dx using the identity sinx=2(sin(x/2)cos(x/2)). I ...
- Calculus - Evaluate ∫ (cos(x))^(1/2)sin(x)dx Let u = cos(x)? ∫ (u)^(...
- Math integrals - What is the indefinite integral of ∫ [sin (π/x)]/ x^...
- Integration? - Sorry, i have a load of questions on integration... thanks for ...
- Calculus 2 Trigonometric Substitution - I'm working this problem: ∫ [1-tan...
- Calculus AP - hi again im really need help TextBook: James Stewart:Essential ...
- Calculus AP - Evaluate the integral interval from [0 to pi] t sin(3t)dt Use ...
- Calculus - Alright, I want to see if I understand the language of these two ...
- Calculus - ∫((cos^3(x)/(1-sin^(2)) What is the derivative of that integral...

More Related Questions