00:01
So given this right triangle with angle theta, suppose i'm going to find the half angle tangent of theta over 2.
00:07
And note that there's two different formulas for tangent of theta.
00:10
This is sign of the original angle over 1 plus cosine of the original angle.
00:16
Or this is equivalent to 1 minus cosine of the original angle over sign.
00:20
It does not matter which one i use as long as i stay consistent.
00:24
Let's use the second one.
00:27
So using the second one involved in finding, sign, cosine, and tangent.
00:32
One acronym to remember the ratios of sign, cosine, and tangent is sign is opposite over hypotenuse, cosine is adjacent over hypotenuse.
00:40
So sign of my angle, in the triangle is the opposite side.
00:45
The side across is seven over the hypotenuse, which is always across from the 90 degree angle...