How Do You Integrate sin^6(x) Using Trigonometric Identities?

AI Thread Summary
To integrate sin^6(x), the problem is transformed into ∫(sin^2(x))^3 dx, leading to the expression (1/8)∫(1 - cos(2x))^3 dx. The discussion highlights the use of half-angle identities for cos^2(2x) and the challenge of integrating cos^3(2x). Suggestions include utilizing sine integral reduction formulas, which simplify the integration of powers of sine. The integration process continues until reaching sin^0(x), confirming the effectiveness of the reduction approach.
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Problem:
\int sin^6 x dx
Progress so far:
\int (sin^2 x)^3 dx
\frac{1}{8} \int (1-cos2x)^3 dx
\frac 1 8 \int (1 - 3cos2x + 3cos^22x - cos^32x) dx

Any help is appreciated.

I can see using a half angle identity for cos^2(2x), but what do I do with the cos^3(2x)?


Steve
 
Last edited:
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Try looking up some sine integral reduction formulas on google. They take care of integrals involving powers of sine pretty nicely.
 
whozum said:
Try looking up some sine integral reduction formulas on google. They take care of integrals involving powers of sine pretty nicely.

I've found one in my text. Would I simply continue using the reduction formula until I get to sin^0(x)?

Steve
 
Yes that's pretty much how we did it.
 
Thanks whozum.

Steve
 
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