f(x)= arctan(2x^2),求 f '(1)

问题描述:

f(x)= arctan(2x^2),求 f '(1)
还有arctan 是什么

4/5是正确答案.
f(x) = arctan(2x²)
f'(x) = (2x²)'/(1 + (2x²)²) = 4x/(1 + 4x⁴)
f'(1) = 4/(1 + 4) = 4/5