Question

Assertion(A): The area bounded by $y^2=4x$ and $y=x$ is $\frac{8}{3}$ sq. units.

Reason(R): The area bounded by $y^2=4ax$ and $y=mx$ is $\frac{8a^2}{3m^3}$ sq. units.

• A. Both A and R are true and R is the correct explanation of A.
• B. Both A and R are true but R is not the correct explanation of A.
• C. A is true but R is false.
• D. A is false but R is true.

Answer 1

The correct option is A Both A and R are true and R is the correct explanation of A.

$\stackrel{4a/m^2}{\underset{0}{\int }}(\sqrt{4x}-x)dx$
$\frac{2}{3}\times 2a^{1/2}{x}^{3/2}-\frac{x^2}{2}{|}_0^{4a/m^2}$
$=8a^2/3m^3$ (R is true)
A is true by inspection
So, A,R are true and R explains A.