Hi, I need to integrate cos^3(x). So far I have:∫cos^3(x) = ∫cos(x)(1-sin^2(x)) = ∫cos(x) -∫cos(x)sin^2(x)= sin(x) - (1/3) sin^3(x) = 1/3 (3sin(x) - sin^3(x)) How do I get from this to: 1/12 (9sin(x) + sin(3x)) Is there a special trig identity?
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Originally Posted by Mr.Ree Hi, I need to integrate cos^3(x). So far I have:∫cos^3(x) = ∫cos(x)(1-sin^2(x)) = ∫cos(x) -∫cos(x)sin^2(x)= sin(x) - (1/3) sin^3(x) = 1/3 (3sin(x) - sin^3(x)) How do I get from this to: 1/12 (9sin(x) + sin(3x)) Is there a special trig identity? . Therefore .
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