sin^2(10)+cos^2(40)+sin10cos40

来源：学生作业学帮网编辑：学帮网时间：2024/05/20 03:46:39

sin^2(10)+cos^2(40)+sin10cos40
=(1-cos20)/2+(1+cos80)/2+1/2(sin50-sin30)
=1+1/2(cos80-cos20)+1/2sin50-1/4
=3/4-1/2sin50+1/2sin50
=3/4

0.75