若sinx/(1+cos)=1/2,求sinx+cosx的值?
问题描述：
若sinx/(1+cos)=1/2,求sinx+cosx的值?
答
(sin(x)/(1+cos(x)))^2 = (1-cos(x)^2) / (1+cos(x))^2
= (1-cos(x)) / (1+cos(x)) = 1/4
=> cos(x) = 3/5
=> sin(x) = 4/5
=> cos(x)+sin(x) = 7/5