Let a function $f(x)$ satisfies $f^{2}(x)-f^{2}(y)=4(x-y)$ and $f(0)= 2\left ( f\left ( x \right )\geq 0 \right )$whose domain is $\left [ a ,\infty \right )$ and it is differentiable on $\left (a ,\infty \right )$

The value of $f(3)$ is

If $f:R\rightarrow R,f(x)=2x+|x|$, then $f(x)+f(-x)$ is

Let $f(-2, 2)\rightarrow(-2, 2)$ be a continuous function given $f(x)=f{(x}^{2})$. Given $f(0)=\dfrac{1}{2}$ then the $4f(\dfrac{1}{2})$

$If\;\phi \left( x \right) = \;\phi '\left( x \right)\;and\;\;\phi \;\left( 1 \right) = 2,\;then\;\;\phi \left( 3 \right)\;equals\;$

$f(x)$ is a linear function. If $f(x)=-1$ and $f(2)=14$ find the value of $f(15)$