View Full Version : Simple derivative problem
calculateme
Feb4-04, 07:35 PM
I am taking basic calculus, and have just got to integration. Can someone please tell me how to find the antiderivative of (sin(x))^4?
matt grime
Feb4-04, 07:45 PM
Looks like home work. Replace a power with a multiple - you can do sin^2 using cos 2, so this is no harder.
calculateme
Feb4-04, 10:39 PM
Sorry, but I still don't understand. How do you find the antiderivative of (sin(x))^2? Could you explain it to me please?
Do you know about the chain rule?
do you know the derivatives of \sin x and x^2?
calculateme
Feb5-04, 12:33 AM
Originally posted by NateTG
Do you know about the chain rule?
do you know the derivatives of \sin x and x^2?
Yes, but how are they going to help me find the antiderivative of sin^4x?
himanshu121
Feb5-04, 01:47 AM
Try to Reduce the power of sin4x by
2sin2x=1-cos2x.
therefore
4sin4x=(1-cos2x)2
i.e 1+cos22x-2cos2x
Again use
2cos22x = 1+cos24x
Simplifying u will obtain
\sin^4x = \frac{3}{8} +\frac{cos4x}{8}-\frac{cos2x}{2}
Hope this will help u
Integral
Feb5-04, 02:18 AM
Himanshu
I think you have a typo
2cos22x = 1+cos24x
Should be
2cos22x = 1+cos4x
himanshu121
Feb5-04, 03:40 AM
Ya typo is there it is
2cos22x = 1+cos4x
error is regretted
calculateme
Feb5-04, 02:11 PM
Himanshu
Thanks a lot, I understand now.
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