- Thread starter Mathsnut
- Start date

- Joined
- Jan 27, 2012

- Messages
- 5,641

I think the idea is to find not the point, but how the lines are oriented relative to the center of the circle.If lines L1 & L2 form a right angle within a circle, at what point P are the lengths of L1 + L2 maximized?

Note: the right angle is not bound to the circumference, but may be placed at any location within the circle.

Pick a point P on the circumference. Draw the 2 lines. Start turning the lines around P. The angle of rotation is your variable. Figure out the length as a function of the angle. Find the maximum.

For −π/2 ≤ θ ≤ π/2 and r = ? < a trig function, do you know it? >

Can you see how this helps?

--

However I am also wondering if you are studying partial derivatives in class? If so, then your teacher probably wants you to solve this question in a different way (by considering ALL points within the circle).