HELP PLEASE!!!! locate the critical points and classify them as stationary points. f(x)=sin^2x, 0
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OpenStudy (anonymous):
Do you know how to find critical points?
OpenStudy (anonymous):
To find critical points you take the derivative and set it to 0 and solve for x, so take the derivative of your problem then set it = 0 and then solve for x.
OpenStudy (rajee_sam):
\[Sin ^{2}X\]
OpenStudy (rajee_sam):
is it ?
OpenStudy (anonymous):
oh no its sin^2 2x
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OpenStudy (rajee_sam):
OK to find the critical points like onegirl said set your first derivative to zero and find the values of x for which it will be = 0
OpenStudy (rajee_sam):
\[f'(x) = 2\sin2xcos2x . 2 = 4 \sin2x \cos2x\]
OpenStudy (rajee_sam):
\[4 \sin2xcos2x = 0\] means either sin2x = 0 or cos2x = 0
OpenStudy (rajee_sam):
your interval given is 0 to 2pi
OpenStudy (anonymous):
how did you get that first derivative?
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OpenStudy (anonymous):
was it with a chain rule?
OpenStudy (rajee_sam):
yes
OpenStudy (rajee_sam):
sin^2 2x - first do the power 2 sin2x, now do the sin2x, which will cos2x and then you have to do the 2x which is 2
OpenStudy (anonymous):
oh okay i see now
OpenStudy (rajee_sam):
|dw:1367703132405:dw|
If you see the curve slope is zero at \[\pi/4 , 3\pi/4, 5\pi/4, 7\pi/4\]