-225-15y-144-12+10=48y-256-17y-17
-15y-48y+17y=-256-17+225+144+12-10
-46y=98
y=-2.13
Х+2 не равно 0
х не равен -2
и х-3 не равен 0
х не равен 3
значит при х= -2 и х=3 не имеет смысла это выражение
А)sin 2t = 2 sint cost
Б)sin40/cos20=2sin20cos20/cos20=2sin20
В)2sin (3t)
Г)cos 2*40 / (cos 40 +sin 40) = (cos^2 40-sin^2 40)/ (cos 40 +sin 40)=
= (cos 40 +sin 40) (cos 40 -sin 40) /(cos 40 +sin 40) = cos 40-sin 40
Д) Формула двойного угла: )
2 Sin 15' Cos 15' = sin 30 = 0,5
Е) (cos75-sin75)^2=cos75^2-2*cos75*sin75+sin75^2=1-2cos75*sin75=1-sin150=1-sin(180-30)=1-sin30=1-0,5=0,5
Для составления уравнения плоскости используем формулу:
<span><span><span>x - xA </span><span>y - yA </span><span>z - zA</span></span></span>
<span><span><span>xB - xA </span><span>yB - yA </span><span>zB - zA</span></span></span>
<span><span><span>xC - xA </span><span>yC - yA </span><span>zC - zA</span></span></span> = 0
Подставим данные и упростим выражение:
<span><span><span>x - (-1) </span><span>y - 7 </span><span>z - (-2)</span></span></span>
<span><span>1 - (-1) (-1) - 7 2 - (-2)</span></span>
<span><span>2 - (-1) 3 - 7 (-1) - (-2)</span></span> = 0
<span><span><span>x - (-1) </span><span><span>y - </span>7 </span><span><span>z - </span>(-2)</span></span></span>
<span><span> 2 -8 4</span></span>
<span><span> 3 -4 1</span></span> = 0
<span><span>(x - </span>(-1))(</span>-8·1-4·(-4)) - (<span><span>y - </span>7)(</span>2·1-4·3) + (<span><span>z - </span>(-2))(</span>2·(-4)-(-8)·3) = 0
8(<span>x - (-1))</span> + 10(<span>y - 7)</span> + 16(<span>z - (-2))</span> = 0
8x + 10y + 16z - 30 = 0
4x + 5y + 8z - 15 = 0
