Question

求下列函数在给定点的导数：⑴f (x )=x ¼,x =5 ⑵f (x )=3（x ＋1）x ∧

Answer 1

1）f'(x)=1/4, 因此f'(5)=1/4

2) f'(x)=3x^2+6x(x+1)=9x^2+6x, f(1)=9+6=15

3) f'(x)=4x+5, f(2)=8+5=13

4) f'(x)=2x(2x+3)+2(x^2+1)=6x^2+6x+2, f'(2)=24+12+2=38