$$\sqrt{4 a^2 (y-b)^2+c^4}=\dfrac1{2|a|}\sqrt{(y-b)^2+\left(\dfrac{c^2}{2a}\right)^2}$$
Using Trigonometric substitutions , set $y-b=\dfrac{c^2}{2a}\cdot\tan u$
and use How to integrate $\sec^3 x \, dx$?
Or Indefinite integral of secant cubed
$$\sqrt{4 a^2 (y-b)^2+c^4}=\dfrac1{2|a|}\sqrt{(y-b)^2+\left(\dfrac{c^2}{2a}\right)^2}$$
Using Trigonometric substitutions , set $y-b=\dfrac{c^2}{2a}\cdot\tan u$
and use How to integrate $\sec^3 x \, dx$?
Or Indefinite integral of secant cubed