• 2022-06-11
    已知f(x)=xe2x,则f’(x)=____
    A: A.(x+2)e2x B.(x+2)ex
    B: C.(1+2x)e2xD.2e2x
  • C

    内容

    • 0

      已知\( y = f({x^2}) \),假设\( f(u) \)二阶可导,则\( y'' \)为( ). A: \( 4{x^2}f''({x^2}){\rm{ + }}2f'({x^2}) \) B: \( {x^2}f''({x^2}){\rm{ + }}2f'({x^2}) \) C: \( 4{x^2}f''({x^2}){\rm{ + }}f'({x^2}) \) D: \( {x^2}f''({x^2}){\rm{ + }}f'({x^2}) \)

    • 1

      【单选题】设 f ( x ) 是可导函数, 则 lim Δ x → 0 f 2 ( x + △ x ) − f 2 ( x ) △ x = ()。 A. [ f ′ ( x ) ] 2 " role="presentation"> [ f ′ ( x ) ] 2 B. 2 f ′ ( x ) " role="presentation"> 2 f ′ ( x ) C. 2 f ( x ) f ′ ( x ) " role="presentation"> 2 f ( x ) f ′ ( x ) " role="presentation"> 2 f ( x ) f ′ ( x ) x ) 2 f ( x ) f ′ ( x ) " role="presentation"> f ( x ) f ′ ( x ) D. 不存在;

    • 2

      【单选题】设 f ( 1-cos x ) =sin 2 x, 则 f ( x ) = A. x 2 +2x B. x 2 -2x C. -x 2 +2x D. -x 2 -2x

    • 3

      已知\( y = {f^2}(x) \),假设\( f(u) \)二阶可导,则 \( y'' \)为( ). A: \( 2{[f'(x)]^2} + 2f(x)f'(x) \) B: \( 2[f'(x)] + 2f(x)f''(x) \) C: \( 2{[f'(x)]^2} + 2f(x)f''(x) \) D: \( 2{[f'(x)]^2} + f(x)f''(x) \)

    • 4

      设f(x)=ln x,g(x)=x+2,则f[g(x)]的定义域是() A: (-2,+∞) B: [-2,+∞) C: (-∞,2) D: (-∞,+∞)