The particular solution of differential equation $$(x+y) d y+(x-y) d x=0$$ at $$x=y=1$$ is

$$\int \frac{10^{\frac{x}{2}}}{\sqrt{10^{-x}-10^x}} d x=$$

$$\int_0^{\pi / 2} \frac{\cos x}{3 \cos x+\sin x} d x=$$

If $$A=\left[\begin{array}{rr}2 & 3 \\ 5 & -2\end{array}\right]$$ and $$A^{-1}=K A$$, then $$K$$ is