1 + tan^2 225 degrees

Using reference angles, (take 225 and subtract 180), you get 45. Since 225° is in quadrant 3, it is positive. Now you have 1 + tan^2 (45°)…

Tan^2 is the same as tan x tan, so you have 1 + tan(45) x tan (45).
If you use a 45-45-90 triangle, you get tan(45) =1. So, 1 + (1x1).
Answer: 2