已知sin^2x-cos^2x=1/5,则tan^2x=

问题描述:

已知sin^2x-cos^2x=1/5,则tan^2x=

sin^2x-cos^2x=1/5,
又sin^2x+cos^2x=1,
所以cos^2x=2/5,
1/cos^2x=5/2
则tan^2x= 5/2-1=3/2