<span>Решение во вложении.</span>
tg540=0 т.к sin540=0
cos(П-3П/4) + 0; -cos(П-П/4)+0= cosП/4 + 0= (корень 2)/2
TgB = AC/BC = 8/√32 = 8√32/32 = <span>√2</span>
Cos²x - 3CosxSinx + 2Sin²x =0
Разделим обе части на Cos²x≠0
![\frac{Cos ^{2} x}{Cos ^{2}x } - \frac{3CosxSinx}{Cos ^{2}x } + \frac{2Sin ^{2}x }{Cos ^{2} x} =0](https://tex.z-dn.net/?f=+%5Cfrac%7BCos+%5E%7B2%7D+x%7D%7BCos+%5E%7B2%7Dx+%7D+-+%5Cfrac%7B3CosxSinx%7D%7BCos+%5E%7B2%7Dx+%7D+%2B+%5Cfrac%7B2Sin+%5E%7B2%7Dx+%7D%7BCos+%5E%7B2%7D+x%7D+%3D0)
tg²x - 3tgx + 2 = 0
tgx = m
m² -3m +2 = 0
D = (-3)² - 4*2 = 9-8=1
m₁ = (3+1)/2 = 2
m₂ = (3 - 1)/2 = 1
tgx =2 tgx = 1
x = arctg2 + πn, n ∈ z x = arctg1 + πn, n ∈ z
x = π/4 + πn, n ∈ z