Question

The area bounded by the parabola $y^2=4ax$, its axis and two ordinates x=4, x=9 is

• A. $4a^2$
  
• B. $4a^2.4$
• C. $4a^2(9-4)$
  
• D. $\frac{152\sqrt{a}}{3}$

Answer 1

The correct option is D $\frac{152\sqrt{a}}{3}$

Shaded area $A=2{\int }_4^9\sqrt{4ax}dx$


$A=4\sqrt{a}\times \frac{2}{3}[x^{\frac{3}{2}}{]}_4^9=\frac{152\sqrt{a}}{3}$