KVPY2019MathematicsApplication of Derivatives
Among all the parallelograms whose diagonals are 10 and 4 , the one having maximum area has its perimeter lying in the interval
Options
- A( 19 , 20 ]
- B( 20 , 21 ]
- C( 21 , 22 ]
- D( 22 , 23 ]
Correct answer
C. ( 21 , 22 ]
Step-by-step solution
Area of parallelogram whose diagonals are 10 and 4 and if angle between adjacent side is θ is A = 10 × 4 sin θ The area will be maximum if θ = π 2 , so the parallelogram must be rhombus Perimeter of rhombus = 4 29 = 464 and 464 ∈ ( 21 , 22 ]