Question

求下列函数在给定点的导数 （1）y=x的1/4次幂,x=16 （2）y=sinx,x=派/2 （3）y=cosx,x=2

Answer 1

(1)

y=x^0.25

y'

=0.25x^(0.25-1)

=0.25x^(-0.75)

y'(16)=0.25/8=1/32

(2)

y=sinx

y'=cosx

y'(π/2)=0

(3)

y=cosx

y'=-sinx

y'(2π)=-1