D = (-1)2 - 4 • 1 • (-2) = 9
1) x-(x-32+2x^2)=0
x-x+32-2x^2=0
-2x^2+32=0
-2x^2=-32
x^2=16
x1=4;x2=-4
(2x-1)/3=5
2x-1=15
2x=16
x=8.
Ответ: х=8.
<span><span>cosa=1/√2 cos²a=1/2
sina=√1-1/2=1/√2 sin²a=1/5
cos2a=cos²a-sin²a=1/2-1/2=0
sin2a=2sinacosa=2*1/√2*1/√2=1
cos2a-coa6a=-2sin(-2a)sin4a=2sin2asin4a=2sin2a*2sin2acos2a=
=4sin²2acos2a=4*</span>1*0=0</span>