This problem appeared in the Bafflers thread as exercise #2 and
has some algebraic solutions. A ship is sailing on a course from
the origin. It follows the path y= 3.14 x. It has a speed of 1 /
3 units per second. A submarine is located at (5,0). The sub
knows the ship is oblivious to its existence. The sub would like
to torpedo the warship. Torpedoes travel at 1 / 2 units per
second and travel in straight lines. The sub commander's hobby
is mathematics. He fires and sinks the ship! What is the
equation of the torpedoes flight? One solution is to realize
that what is required is triangle with one side being the line y
= 3.14 x the base being the x axis from 0 to 5 and some line
passing through (5,0) and intersecting y = 3.14 x. See fig 1.
With the condition that the red line is 1.5 times longer than
the other side of the triangle. Let's use Geogebra to solve the
problem. 1)Draw the point (5,0) and call it Sub. 2)Enter in the
input bar f(x) = 3.14 x 3)Place a slider on the drawing. Set it
at Min=0 and Max = 10