Questions in differentiation

Select	Question
	The perimeter of a sector is p. The area of the sector is maximum when its radius is
	If $y=a\,\,\log x+b{{x}^{2}}+x$ has its extremum value at $x=1$ and $x=2,$ then $(a,b)$ =
	In $(-4,\,4)$ the function $f(x)=\int\limits_{-10}^{x}{({{t}^{4}}-4){{e}^{-4t}}dt}$ has
	On [1, e] the greatest value of ${{x}^{2}}\log x$
	The function $f(x)={{x}^{-x}},\,(x\,\in \,R)$ attains a maximum value at x =
	If $ab=2a+3b,\,a>0,\,\,b>0$ then the minimum value of ab is
	If PQ and PR are the two sides of a triangle, then the angle between them which gives maximum area of the triangle is
	The function $y=a(1-\cos x)$ is maximum when $x=$
	The minimum value of $\left( {{x}^{2}}+\frac{250}{x} \right)$ is
	The minimum value of ${{x}^{2}}+\frac{1}{1+{{x}^{2}}}$ is at