微分不懂请高手指导.(1/1+4x^2)dx=d()(1/1+4x^2)dx=d().这是不懂的,请一定写明过程,题没写明白，重新写。{1/（1+4x^2)}dx=d()

Question

微分不懂请高手指导.(1/1+4x^2)dx=d()
(1/1+4x^2)dx=d().这是不懂的,请一定写明过程,
题没写明白，重新写。{1/（1+4x^2)}dx=d()

Answer 1

[1/(1+4x^2)]dx = (1/2) [1/(1+4x^2)]d(2x) = (1/2)d[arctan(2x)]