(Cosα - Sinα)² + 2SinαCosα = Cos²α - 2SinαCosα + Sin²α + 2SinαCosα =
= Cos²α + Sin²α = 1
20x^2-14x=0
x(20x-14)=0
x=0 или 20x-14=0
x=0.7
∫sinxcosxdx = ∫0,5sin2xdx = ∫0,25sin2xd(2x) = -0,25cos2x + C
Ах+в=0
Примеры:3х+в=0
10х+в=0
D = 11-7 = 4
a1 = 7-4 = 3
S= (2a1 +d(n-1))*16/2 =(6+4*15)*8 = 528