要使等式sinA加cosA =(2m-3)/(2-m )有意义,求m的取值范围.
问题描述:
要使等式sinA加cosA =(2m-3)/(2-m )有意义,求m的取值范围.
答
sinA+cosA=(2m-3)/(2-m)
=√2sin(x+A)
值域为 [-√2,√2]
所以
|(2m-3)/(2-m)|≤√2
|[2(m-2)+1]/(m-2)|≤√2
|2+[1/(m-2)]|≤√2
-√2-2≤1/(m-2)≤√2-2
m-2