Question

求y=x^(1/2)-x^(-1/2)的导函数

Answer 1

公式(x^n)'=nx^(n-1)

f(x)=v(x)+-u(x),f'(x)=v'(x)+-u'(x)

y=x^(1/2)-x^(-1/2)

y'=[x^(1/2)]'-[x^(-1/2)]'

=1/2*x^(1/2-1)-(-1/2)*x^(-1/2-1)

=x^(-1/2)/2+x^(-3/2)/2

=[x^(-1/2)+x^(-3/2)]/2

反函数自己求吧~用比例,几下就出来了