f(x) = sin(x), g(x) = cos(x) とすると、
d/dx tan(x)
= d/dx (sin(x)/cos(x))
= d/dx (f(x)/g(x))
= ( f'(x) g(x) - f(x) g'(x) )/( g(x))^2
= (cos(x) cos(x) - sin(x) (- sin(x)))/(cos(x))^2
= ((cos(x))^2 + (sin(x))^2 )/(cos(x))^2
= 1 /(cos(x))^2
最新の画像［もっと見る］
