Read the two statements and choose the correct option.
I. Of all rectangles with a given perimeter, the square has the largest area.
II. Of all closed cylinders with a given volume, the one with the least surface has its height equal to its radius.

Only ICorrect answerYour answerOnly IICorrect answerYour answerBoth I and IICorrect answerYour answerNeither I nor IICorrect answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer A

Correct answer: A

With perimeter $2s$ , the area $x(s - x)$ is largest at $x = \frac{s}{2}$ : equal sides, a square. I is true.
For the cylinder the best height is the diameter, $h = 2r$ , not the radius, so II is false.

Ten questions from Maxima & Minima, at your own pace.

Read the two statements and choose the correct option.I. Of all rectangles with a given perimeter, the square has the largest area.II. Of all closed cylinders with a given volume, the one with the least surface has its height equal to its radius.