Mathematics

Mathematics

Problem

The maximum volume (in cu.m) of the right circular cone having slant height 3 m is (a) 6π6\pi (b) 33π3\sqrt{3}\pi (c) 43π\frac{4}{3}\pi (d) 23π2\sqrt{3}\pi
Intuitive explanation

A cone's volume depends on both its height and base radius, but they're linked by the fixed slant height constraint ℓ=3\ell = 3. The key insight is to express volume in terms of just one variable using the Pythagorean relationship ℓ2=h2+r2\ell^2 = h^2 + r^2, then optimize by finding where dVdh=0\frac{dV}{dh} = 0. This transforms a constrained geometry problem into a single-variable calculus problem.

Intuitive explanation

A cone's volume depends on both its height and base radius, but they're linked by the fixed slant height constraint ℓ=3\ell = 3. The key insight is to express volume in terms of just one variable using the Pythagorean relationship ℓ2=h2+r2\ell^2 = h^2 + r^2, then optimize by finding where dVdh=0\frac{dV}{dh} = 0. This transforms a constrained geometry problem into a single-variable calculus problem.

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