Subject GRE-Style: Optimization Without a Calculator

GRE Math Subject · Axiom Academy

EXAMPLE GRE-Style Optimization Without a Calculator Substitute into the surface area formula: Take the derivative and set it equal to zero: Using the constraint with the optimal radius: This simplifies to the expression in option (C). Since the second derivative is positive for all r > 0 , this is indeed a minimum. GRE Insight: The key to these optimization problems is using the constraint to reduce dimensions. You don't need a calculator—just keep it symbolic and match the answer form.

This is the written version of the interactive lesson above. See the full GRE Math Subject course.