y=sin^4x/4+cos^4x的导数怎么求?打错了,是y=sin^4(x/4)+cos^4(x/4)

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y=sin^4x/4+cos^4x的导数怎么求?打错了,是y=sin^4(x/4)+cos^4(x/4)y=sin^4x/4+cos^4x的导数怎么求?打错了,是y=sin^4(x/4)+cos^4(

y=sin^4x/4+cos^4x的导数怎么求?打错了,是y=sin^4(x/4)+cos^4(x/4)
y=sin^4x/4+cos^4x的导数怎么求?
打错了,是y=sin^4(x/4)+cos^4(x/4)

y=sin^4x/4+cos^4x的导数怎么求?打错了,是y=sin^4(x/4)+cos^4(x/4)
y=sin^4(x/4)+cos^4(x/4)
=[sin^2(x/4)+cos^2(x/4)]^2-2sin^2(x/4)cos^2(x/4)
=1-1/2sin^2(x/2)
=1-1/4(1-cosx)
=3/4+1/4cosx
y′=-1/4sinx

cos(x/4)sin^3(x/4)-sin(x/4)cos^3(x/4)