Question

求函数的一阶导数1.f(x)=3x'2-5x+32.f(x)=2x+1/3x3.f(x)=sinxcosx4.f(x)=

Answer 1

1.f(x)=3x'2-5x+3

f'(x)=2×3x-5

=6x-5

2.f(x)=2x+1/3x

f'(x)=2+1/3*(-1/x²)

=2-1/(3x²)

3.f(x)=sinxcosx

f(x)=(sin2x)/2

所以f'(x)=cos2x*(2x)'/2

=2(cos2x)/2

=cos2x

4.f(x)=ln(x'2+1)

f'(x)=[1/(x²+1)](x²+1)'

=2x/(x²+1)