А)пример=((a^2+b^2+2ab)/2<u>ab)</u>*<u>ab</u>=(a+b)^2/2
B)пример=<span> 2c/b+((b-c)^2*((b+c)*(b-c)+(b-c)^2)/((b-c)^3*(b+c))= 2c/b+c+2b/b+c=2(b+c)/b+c=2</span>
2sin^2(x)+(3+2√3)sin( x )cos( x )+3 √3 cos^2(х)=0 /cos²x
2tg²x+(3+2√3)tgx+3√3=0
tgx=a
2a²+(3+2√3)a+3√3=0
D=9+12√3+12-24√3=9-12√3+12=(3-2√3)²
√D=2√3-3
a1=(-3-2√3-2√3+3)/4=-√3⇒tgx=-√3⇒x=-π/3+πk,k∈z
a2=(-3-2√3+2√3-3)/4=-1,5⇒tgx=-1,5+πk,k∈z
k=0 x=-60гр и х=-arctg1,5
Ответ х=-60гр
√250=√(25*10)=5√10
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X = - 4/5 = -0,8
(-0,8 - 4)(-0,8 ^2 + 2 * (-0,8) - 5) - (-0,8) ^ 3 =
-4,8 * (-4,52) + 0,512 = 11, 108352