(1)已知0<x<π/2 ,cosx=4/5,则tanx= (2)函数y= cos(3π/2 -x)/cos(3π-x)最小正周期是

问题描述:

(1)已知0<x<π/2 ,cosx=4/5,则tanx= (2)函数y= cos(3π/2 -x)/cos(3π-x)最小正周期是

(1)cosx=4/5,sinx=3/5则tanx=3/5/4/5=3/4 (2)cos(3π/2 -x)=cos(x+π/2)=-sinx cos(3π-x)=-cosx y= cos(3π/2 -x)/cos(3π-x)=tanx 所以最小正周期π