"It's milking time at the farm, and the milkmaid has been
sent to the field to get the day's milk. She's in a hurry to
get back for a date with a handsome young goatherd, so she
wants to finish her job as quickly as possible. However, before
she can gather the milk, she has to rinse out her bucket in the
nearby river.
Just when she reaches point
M, our heroine spots the
cow, way down at point
C. Because she is in a hurry, she
wants to take the shortest possible path from where she is to the
river and then to the cow. So what is the best point
P on
the riverbank for her to rinse the bucket?"
An Introduction to Lagrange Multipliers
