設函數y=sin(x^2-1),則dy=
dy=
cos(x^2-1)(x^2-1)'dx
=cos(x^2-1)*2xdx
=2xcos(x^2-1)dx
設函數y=sin x / e的x次方,求dy
dy=[(cosx-sinx)/e^x]*dx
求函數y=cos(x^2)·sin^2(1/x)的微分dy .
y=cos(x^2)·sin^2(1/x)y'=-2xsin(x²)sin²(1/x)+cos(x²)2sin1/x cos1/x·-1/x² =-2xsin(x²)sin²(1/x)-1/x² cos(x²)sin2/x所以dy=【-2xsin(x²)si…
求函數y=sin^3x在x=∏/3,△x=0.01時的微分dy
dy=3sin^2xcosxdx
當x=∏/3,△x=0.01時dy=3*(3/4)*(1/2)*0.01=0.01125
根據複合函數微分法則y-sin(2x+1),求dy
y=sin(2x+1)
dy=dsin(2x+1)
=cos(2x+1)d(2x+1)
=2cos(2x+1)dx
設函數y(x)由方程xcosy+ylnx=0確定,則dy/dx=?麻煩寫出過程和原因.
用隱函數求導法則:注意y是關於x的函數,方程兩邊對x求導有
(x)'cos y+x(cosy)'+(y)'lnx+y(lnx)'=0
即
cos y-x(siny)y'+y'lnx+y(1/x)=0,
根據上述方程解出y',即得.