若方程sinx+cosx=k在x∈[0,π]有两解,则k的范围

问题描述:

若方程sinx+cosx=k在x∈[0,π]有两解,则k的范围

sinx+cosx
=√2*(√2/2*sinx+√2/2*cosx)
=√2*(sinxcosπ/4+cosxsinπ/4)
=√2*sin(x+π/4)
0