<span>y' = tg' x + ctg' x = 1/(cos^2 (x) ) + (- 1/(sin^2 (x) ) = 1/(cos^2 (x) ) - 1/(sin^2 (x) ) = 1/(sin^2 (x) * cos^2 (x) ) = [(1-cos(2x))/2 ]*[(1+cos(2x))/2] = (1-cos^2 (2x) )/4</span>
4.5/1.5=3 кг хлеба из кг муки
3*70000=210000 = 210 т хлеба.
отв:210т хлеба
(x^2-4x+3)(x-5)=x^3-4x^2+3x-5x^2+20x-15=x^3-9x^2+23x-15