^-знак возведения в степень
1.
1) = 9b^2-25
2) = 64y^2-25x^2
3) = 0,25x^6-0,04y^8
4) = x^14-y^6
5) = y^8n-y^2n
2. 1) -2y^2(3y+1)(1-3y)=-2y^2(1-9y^2)=18y^4-2y^2
2) = (a^10+b^10)(a^10-b^10)=a^20-b^20
3. =0= x^2-4-x^2+6x ---> x=4/6=2/3
4. 1) (3b-4x)(3b+4x)=9b^2-16x^2
2) (2a+7b)(2a-7b)=4a^2-49b^2
X²-ax+3=2x-1 x²-(a+2)x+4=0
D=0 a²-4a-4-16=a²-4+4=0
a1=-2 a2=2
Cos(a-π/6)*cos(a+π/6)=1/2(cos(a-π/6-a-π/6)+cos(a-π/6+a+π/6))=
=1/2(cos(-π/3)+cos2a)=1/2*cosπ/3+1/2cos2a=1/2*1/2+1/2*cos2a=
=1/4+1/2*cos2a
B[n]=b[1]*q^n-1
18=2*q^4
9=q^4
q=sqrt(3) sqrt=<span>1.73205080757
b[3]=2*(sqrt(3))2
b[3]=2*3
b[3]=6
b[5]-b[3]=18-6=12
Ответ: 12
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