Chemegate

GATE 2024 Chemical Engineering, Q47 · Mathematics

The correct answer is A, 3πa²/2.

Question

Let r and θθ be the polar coordinates defined by x = r cos θθ and y = r sin θ.θ. The area of the cardioid r = a(1 cos θ),0θ2π,θ), 0 \leq θ \leq 2π, is

Figure for Q47 (Mathematics, Polar Coordinates): Let r and θ be the polar coordinates defined by x = r cos θ and y = r sin θ. The area of the cardioi…
  • A. 3πa2/23πa²/2
  • B. 2πa2/32πa²/3
  • C. 3πa23πa²
  • D. 2πa22πa²

Official answer: 3πa2/23πa²/2

Why

GATE 2024 official key: (A). The area enclosed by the cardioid r=a(1cosθ)r=a(1−cosθ) is a standard result: Area =(1/2)02πr2dθ=3πa2/2.= (1/2)\int ₀^{2π} r² dθ = 3πa²/2.

Explanation cross-checked for consistency. Final answer matches the official IIT answer key.