Question

Area bounded by the parabola $y = 4x^{2},$ $y -$axis and the lines $y = 1,y = 4$ is

• A. 3 sq. unit
• B. $\frac{7}{5}$sq. uni
• C. $\frac{7}{3}$sq. unit
• D. None of these

Answer 1

Answer: (C)

$\frac{7}{3}$sq. unit

Answer 2

Required area = $\int_{1}^{4}{xdy = \int_{1}^{4}{\frac{\sqrt{y}}{2}dy}}$

= $\frac{1}{2}.\frac{2}{3}|y^{3/2}|_{1}^{4} = \frac{7}{3}$ sq. unit.