A rectangle of length ‘x’ and breadth ‘y’ is inscribed in a semi-circle of fixed radius ‘r’ as shown in the figure given below.
Based on the above information answer the following question:
The value of θ, for which A'(θ) = 0 is
Answer & explanation
Correct answer: option 3
$A'(θ)=0$
$A=r^2sin2θ$
$A'=2r^2cos2θ=0$
$2θ=(2n+1)\frac{\pi}{2}$
$θ =(2n+1)\frac{\pi}{4}⇒θ = \frac{\pi}{4}$
Option C is correct.