证明:假设三角形中有两个直角,则第三个角的度数为 ,则不能构成三角形,故假设错误,原命题成立,故得证.
The findings support another study which showed that being happy ______ reduce the risk of heart disease.
一次函数y=kx+b的图象如图所示,则k、b的值为( )