The equation of the normal at $t=\frac{\pi}{2}$ to the curve $x=2 \sin t, y=2 \cos t$ is

If the function $f(x)=\frac{x}{5}+\frac{5}{x},(x \neq 0)$ attains its relative maximum value at $x=\alpha$, then $\sqrt{\alpha^2+2 \alpha-6}=$

The equation of the tangent to the curve $x^2+y-7=4 x$ at the point $(1,10)$ is

If $\theta$ is the angle between the curves $x^2-y^2=4$ and $y^2=3 x$, then $\tan \theta=$