If you meant what you asked, the answer is 13.2994. A more interesting question with that sequence would be tan(10°)* tan(20°)*tan(30°)* … * tan(80°) = ? Because tan(90°−x) = cotx = 1/tanx, tan(10°)* tan(80°) = tan(10°)*1/tan(10°) = 1. Similarly, the rest of the sequence cancels out with the final answer being 1. However, as a wall, I’m more into geometry than trigonometry – give me more than one right angle, please.