Сначала:
arcCos√3/2 = π/6
arcSin√2/2 = π/4
arc tg √3 = π/3
Теперь решаем:
а) Cos(π + π/6) = -Сosπ/6 = -√3/2
б) Cos(π/2 - π/3) =Sinπ/3 = √3/2
в) 8Sin x = 7Cos x |: Сosx ≠0
8tg x = 7
tgx = 7/8
x = arctg(7/8) + πk, k∈Z
<span>(х+2)²=(х-4)²
x</span>²+4x+4=x²-8x+16
4x+4=-8x+16
4x+8x=16-4
12x=12
x=12:12
x=1
Решение. Пометки не переписывать.
9x^2 + 24x + 16 - (9x^2 - 1) - 65 = 0
9x^2 + 24x + 16 - 9x^2 + 1 - 65 = 0
24x + 16 + 1 - 65 = 0
24x + 17 - 65 = 0
24x - 48 = 0
24x = 48
x = 2