tg(p/3-a)=(tgpi/3-tga)/(1+tgpi/3tga)=(√3-tga)/(1+√3tga)
(√3-tga)/(1+√3tga)=m
√3-tga=m+m√3tga
-tga-√3tga=m-√3
tga+√3tga=√3-m
tga(1+√3)=√3-m
tga=(√3-m)/(1+√3)
sin(a+b)*sin(a-b) = (sina*cosb + cosa*sinb)*(sina*cosb - cosa*sinb) =
2(2-х)-(у+6)=0
х+2у= -1
4-2х-у-6=0
х+2у= -1
у= -2х-6
х+2(-2х-6)= -1
х+2(-2х-6)= -1
х-4х-12= -1
-3х= 11
х= -11/3= -3 2/3
х= -3 2/3
у= -2*(-11/3)-6= 1 1/3
a³ - b³ = (a - b)(a² + ab + b²)
a³ + b³ = (a + b)(a² - ab + b²)
a² - b² = (a - b)(a + b)
(x³ - 1)(x⁶ + x³ + 1) = x⁹ - 1
(x³ + 1)(x⁶ - x³ + 1) = x⁹ + 1
(x³-1)(x³+1)(x¹⁸+1)(x³⁶+1)(x⁶+x³+1)(x⁶ -x³+1) = (x⁹ - 1)(x⁹ + 1)(x¹⁸+1)(x³⁶+1) = (x¹⁸-1) (x¹⁸+1)(x³⁶+1) = (x³⁶-1)(x³⁶+1) = x⁷²- 1