Sin³x-7sinxcos²x+6cos³x=0 (cos³x≠0)
tg³x-7tgx+6=0
tgx=y
y³-7y+6=0
(y-1)(y-2)(y+3)=0
y₁=1;y₂=2;y₃=-3
1) tgx=1;x=π/4+πn,n∈Z
2) tgx=2;x=arctg2+πk,k∈Z
3) tgx=-3;x=-arctg3+πm,m∈Z
A)<u />14a^2x/21ax=2a/3 Б)7а+5a^2/7а=a(7+5а)/7а=7+5а/7 В)3а-3b/а^2-b^2=3(а-b)(а-b)(а+b)=3/а+b
(a²-1)/(a-b) *(7a-7b)/(a²+a) =(a-1)(a+1)*7(a-b) /(a-b)*a(a+1) =7(a-1) /a =(7a -7) /a