Question

A, B are fixed points with coordinates (0,a) and (0,b) (a>0,b>0). P is a variable point (x,0) referred to as the rectangular axis. If the angle $\angle$APB is maximum, then

• A. x2=ab
• B. x2=a+b
• C. x=$\frac{1}{ab}$
• D. x=$\frac{a+b}{2}$

Answer 1

Answer: (A)

x2=ab

Answer 2

The angle ∠APB is maximum when point P is on the x-axis, so x = 0.

The correct answer is option (B): x2=a+b