13x+7-10x+4=17
3x+11=17
3x=17-11
3x=6
x=2
Примечание:Для удобства "а" заменено на "x"
<span>а) sin α =√3/2α=(-1)ⁿ+πn, n∈Z
б) cos α = - √2/2α=+-3π/4+2πn, n∈Z
в) tg α = √ 3α=π/3+πn, n∈Z
г) ctg α = -1α=3π/4+πn, n∈Z
вычислите:а) tg²α + ctg²α=tg²α + ctg²α+2ctgα*tgα-2ctgα*tgα=(tgα+ctgα)²-2ctgα*tgα=(tgα+ctgα)²-2=3²-2=7
б)(3*sin α - 4*cos α)/(5*sin α + 6*cos α)
tgα=-3sinα/cosα=-3sinα=-3cosα(3*sin α - 4*cos α)/(5*sin α + 6*cos α)=(3(-3cosα)-4cosα)/(5(-3cosα)+6cosα) =-13cosα/(-9cosα)=13/9
</span>
arcsin √2/2 - arcos0 + (arctg √ 3)/ (arcctg√3/ 3)=π/4-π/2+π/3:π/3=1-π/4
Х^2-6х+9
4а^2+20ab+25b^2
a^2-4
9x^2-y^2
(4x^2-1)(x^2-9)=0
(2x-1)(2x+1)(x-3)(x+3)=0
x=1/2
x=-1/2
x=3
x=-3
Вынесем за скобки 1/9^2
Получим (1/81)(9-19*9)=(1/9)*(1-19)=-18/9=-2