If sinxα+cosxα≥1, 0<α<π2, then
x∈[2,∞)
x∈−∞,2
x∈[−1,1]
x∈ℝ
[SolutionStep1]:
sinxα+cosxα≥1, 0<α<π2
Since equality holds for x=2
If x<2, both cosα and sinα increase (being + ve fraction).
cosxα+sinxα>1 if x<2
Thus x≤2 i.e. x∈(-∞,2]