√2+√2=2√2
-------------------------------
А) ...=cos(π/15 + 4π/15) /sin(0,3π+0,2π)=cos(π/3) / sin (π/2)= 1/2 : 1 = 0,5
б) ...= tg(2π/3 - 5π/12)= tg(π/4)=1
в) ...=tg (π/10+3π/20)= tg (π/4)= 1
г) ...= - sin (5π/18 -π/9) / cos(5π/12+7π/12) = - sin(π/6) / cos (π) = -1/2 : -1 =1/2
(x+9)(2x+8)=2
2x²+8х+18х+72=2
2х²+26х+70=0
х²+13х+35=0
D=13² - 4*35=29=+-√29
х1=( -13+√29)/2
ч2=( -13-√29)/2
X-ширина
2x-2 - длина
44=2(x+2x-2)
44=6x-4
6x=48
x=48/6
x=8
ширина =8
длина=8*2-2=14