- #1
grafs50
- 16
- 0
Homework Statement
∫(sin2(πx)*cos5(πx))dx.
Homework Equations
Just the above.
The Attempt at a Solution
I have no idea how pi effects the answer, so I basically solved ∫(sin2(x)^cos5(x))dx.
∫(sin2(x)*cos4(x)*cos(x))dx
∫sin2(x)*(1-sin2(x))2*cos(x))dx
U-substitution
u = sin x du = -cos x dx
∫(u2*(1-u2)2) -du
-∫(u2*(1-u2)2) du
-∫(u2*(1-2u2+u4) du
-∫(u2-2u4+u6) du
-((u3/3)-(2u5/5)+(u7/7).
When I look up what the antiderivative should be on integral-calculator.com. the minus sign outside of the parentheses disappears, which I can't figure out how.
Can anyone give me some help?