Applications of Integration · Easy problem

$\displaystyle\int_0^2\sqrt{1+4x^2}\,dx$

$\displaystyle\int_0^{3}\sqrt{1+4x^2}\,dx$

$\displaystyle\int_0^4\sqrt{1+4x^2}\,dx$

$\displaystyle\int_0^2\sqrt{1+4x^3}\,dx$