Question

高中数学题..高手进

1+sin(180-y)cos(90+y)=?

Answer 1

sin(180-y)=siny cos(90 y)=-siny 原式=1-sin方y=cos方y

Answer 2

用诱导公式1+sin(180-y)cos(90+y)=1+siny(-siny)=1-sin^2y=cos^2y

Answer 3

原式=1+siny(-siny)
=1-sin^2y
=cos^2y
用两次诱导公式就行了

Answer 4

1+sin(180-y)cos(90+y)=1+siny*(-siny)=1-sin^2y=cos^2y

Answer 5

我是菜鸟。。。来打酱油的。