1.(m+n)^3+(m-n)^3-2m=(m+n+m-n)(m²+2mn+n²-m²+n²+<span>m²-2mn+n²)-2m=2m(m²+2n²-1)
2. </span>(a-b)^3-(c+d)^3-a+b+c+d=(a-b-c-d)(a²-2ab+b²+ac+ad-bc-bd+c²+2cd+d²)-(a-b-c-d)=(a-b-c-d)(a²-2ab+b²+ac+ad-bc-bd+<span>c²+2cd+d²-1)</span>
<span>Воспользуемся формулой суммы тангенсов:</span>
<span>tg(x/3 + pi/4)+tg(x/3 - pi/4)=sin(2x/3)/(cos(x/3+pi/4)*cos(x/3-pi/4)=</span>
<span>sin(2x/3)/(0.5(cos(pi/2)+cos(2x/3))=2tg(2x/3)</span>
X^(-7*2) * X^-3*(-4) / X^6*(-1) *X^-2*(-3)=
=x^-14 * x^12 / x^-6 *x^6=
=x^-14+12 / x^-6+6=
=x^-2/x^0=
=x^-2-0=
=x^-2 или 1/x^2