у = - х^2 + 3х + 2
y' = (-х^2 + 3х + 2)' = -2x + 3
k = f'(1) = -2 * 1 + 3 = -2 + 3 = 1
tg α = k = 1 => α = arctg 1 = 45°
ответ: α = 45°.
