隻是打比方,意思說有時物理的數學形式會導出不make sense 的解。
Example
Given: side a = 20, side c = 24, and angle C = 40°. Angle A is desired.
Using the law of sines, we conclude that
Note that the potential solution A = 147.61? is excluded because that would necessarily give A + B + C > 180?.
https://en.wikipedia.org/wiki/Law_of_sines