How do I integrate sin^4(2x) ? Note: The 4 is the power but the 2x is not. I tried and I got 3/8x - (1/8)sin4x + (1/64)sin8x + c but the answer is 1/32(48x-4sin4x+sin8x)+c..
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Originally Posted by Tutu How do I integrate sin^4(2x) ? Note: The 4 is the power but the 2x is not. I tried and I got 3/8x - (1/8)sin4x + (1/64)sin8x + c but the answer is 1/32(48x-4sin4x+sin8x)+c.. Here's a quick run-down. First a variable change. Let y = 2x, etc Clever trick warning!! And from . Plugging this in: See what you can do from here. -Dan
When I let y=2x why do.I take the 1/2 out? Is it because cause 2x=2sinxcosx?.thanks!
Originally Posted by Tutu When I let y=2x why do.I take the 1/2 out? Is it because cause 2x=2sinxcosx?.thanks! It is the subsitution rule for integration. dy=2dx --> dy/2=dx Normally you will see the variable 'u' used instead of 'y'... but which you use doesn't matter.
Hello, Tutu! I tried and I got: . . You are right! but the answer is: . . They are wrong! Here are my steps: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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