Question

Решите любое , срочно

Answer 1

$3)\; \; A=\left(\begin{array}{ccc}-1&2&3\\5&1&4\\-2&3&1\end{array}\right)\; \; \; \to \; \; \; 3A=\left(\begin{array}{ccc}-3&6&9\\15&3&12\\-6&9&3\end{array}\right)\\\\\\A^{T}=\left(\begin{array}{ccc}-1&5&-2\\2&1&3\\3&4&1\end{array}\right)\; \; \; ,\; \; \; M_{31}=\left|\begin{array}{cc}2&3\\1&4\end{array}\right|=2\cdot 4-1\cdot 3=5$

$7a)\; \; \int cos(2x-6)\, dx=[\; t=2x-6\; ,\; dt=2\, dx\; \to \; \; dx=\frac{dt}{2}\; ]=\frac{1}{2} \int cost\, dt=\\\\=\frac{1}{2}\cdot sint+C=\frac{1}{2}\cdot sin(2x-6)+C\\\\\\7b)\; \; \int\limits^2_1\, (3x^2+2x+1)\, dx=(3\cdot \frac{x^3}{3}+2\cdot \frac{x^2}{2}+x)\Big |_1^2=(x^3+x^2+x)\Big |_1^2=\\\\=(8+4+2)-(1+1+1)=11$