∵π/2＜θ＜π ∴sinθ＞0,cosθ＜0 即(m-3)/(m+5)＞0且(4-2m)/(m+5)＜0 等价于(m-3)(m+5)＞0且(m-2)(m+5)＞0 即m＞3或m＜-5 且m＞2或m＜-5 ∴m＞3或m＜-5 又sinθ+cosθ=1 ∴(m-3)+(4-2m)=(m+5) 即5m-22m+25=m+10m...