y=sin(x+10°)+cos(x+40°)的最大值
问题描述：
y=sin(x+10°)+cos(x+40°)的最大值
答
y=sin(x+10°)+cos(x+40°)=sin(x+10°)+cos(x+10°+30°)=sin(x+10)+cos(x+10)cos(30)-sin(x+10)sin(30)=0.5sin(x+10)+cos(x+10)cos(30)=sin(x+10+60)=sin(x+70) 所以最大为1 当x=20时取到