Points D, E, and F are the midpoints of sides BC, CA, and AB, respectively, of triangle ABC respectively, and CZ is an altitude of the triangle. If angle BAC = 71, angle ABC = 39, and angle BCA = 70, then what is angle EZD+angle EFD in degrees?
In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.