3.36-4.2x=4.2
-4.2x=0.84
x=-0.2
Sina/2+cosa/2=-1/2 ;3π/2<a<2π
sin2a=?
sin2a=2*sina*cosa
sina=2*sina/2*cosa/2
(sina/2+cosa/2)²=(-1/2)²
sin²a/2+2*sina/2*cosa/2+cos²a/2=¹/4
1+sina=1/4
sina=1/4-1
sina=-3/4
cos²a=1-sin²a=1-9/16=7/16
cosa=√7/4 ;(3π/2<a<2π)
sin2a=2*sina*cosa=2*(-3/4)*√7/4=
-6√7/16
(3π/2<a<2π;3π<2a<4π;sin2a<0)
1) log2(x^2 - 2x) = 3
x^2 - 2x = 2^3
x^2 - 2x - 8 = 0
x1 = -2 x2 = 4
<span>2) log3(x-2)<2
x - 2 < 3^2
x < 11
</span>
У²+8ху+16х²=(у+4х)²
Ответ---- ((у+4х)²)