A)y<span>²-8a+16</span>
б)49x²+14ах+а<span>²
в)25с</span><span>²-1
г)9а</span>²-4b<span>²
</span>2.a²-18a+81-81-2a=a²-20a
1) sinα = - 3/8; sin²α = 9/64; cos²α = 1 - 9/64 = 55/64 ⇒ 5 - 6 cos2α =
5 - 6 · (cos²α - sin²α) = 5 - 6 · (55/64 - 9/64) = 5 - 6 · 46/64 =
5 - (3 · 46) : 32 = 22/32 = 11/16
-0,42х² - 0,28х + 0,18х +0,12 =0
-0,42х² - 0,1х +0,12 = 0|*100
42х² +10х -12 = 0|:2
21х² +5х -6 = 0
D = 529
x = (-5 +-√529)/42
х₁ = (-5+23)/42 = 18/42=3/7
х₂= (-5-23)/42 = -28/42 = -14/21 = =2/3
<em><span>pi<X<3pi/2 -это 3 четверть </span></em>
<em>sinx=+-v(1-cos^2x)=+-v(1-(5/13)^2)=+-v(1-25/169)=+-v(144/169)=+-12/13</em>
<em>т.к. синус в 3 четверти отрицательный то :</em>
<em>sinx=-12/13</em>
У^2 4×^2
--- - ----
у-2х у-2×
у^2-4×^2
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у-2×