Gravitation and orbits homework problem

[Dewgale]

Gneill, he was working from the geometric fact that if you draw a line from the two focii to a point on an ellipse, the angle between the tangent at that point and each line is the same, following from the link I'd posted in post #20. One can then easily derive the angle between the position vector and the velocity if one knows the length of the semilatus rectum.

 

[Physics_Boi]

Ok thank you for the help! I plugged in the values into the equation, and solved. I got the correct answer.