If x belongs to (0, Pai / 2), what is the maximum and minimum value of F (x) = (SiNx + 2) (cosx + 2)

If x belongs to (0, Pai / 2), what is the maximum and minimum value of F (x) = (SiNx + 2) (cosx + 2)

F (x) = sinxcosx + 2 (SiNx + cosx) + 4, let SiNx + cosx = t x belong to (0, Pai / 2), t = SiNx + cosx ∈ (1, √ 2] 1 + 2sinxcosx = T ^ 2, sinxcosx = (T ^ 2-1) / 2F (t) = T ^ 2 / 2 + 2T + 7 / 2 = (T + 2) ^ 2 / 2 + 3 / 2T = 1, Fmin = 6, the minimum t = √ 2, Fmax = 9 / 2 + 2 √ 2