MHT CET2007MathematicsApplication of Derivatives
The maximum area of the rectangle that can be inscribed in a circle of radius r , is
Options
- Ar²
- Br²
- Cr² / 4
- D2 r²
Correct answer
D. 2 r²
Step-by-step solution
Area of rectangle, aligned A &=2 x 2 r²-x² &=4 x r²-x² d A d x &= 4 (r²-2 x² ) r²-x² aligned For maximum or minimum put d A d x =0 x=r / 2 It can be easily checked that d² A d x² < 0 for this value of x . A is maximum for x= r 2 and the maximum value of A is given by A=4 r 2 r²- r² 2 =2 r²