y = (1-sinx)/(2cosx+3) ≥ 0 ∵1-sinx = 2ycosx+3y 2ycosx+sinx = 1-3y √[(2y)²+1] sin(x+T) = 1-3y .tanT=2y 1-3y≤√[(2y)²+1] 1-6y+9y²≤4y²+1 ∴5y²-6y=y(5y-6)≤0 ∴ 0≤y≤6/5...