Why did you feel "the necessity" ?
Naturally, because my game is largely physics based, I felt the necessity to design a lookup table for my trig functions.
Twenty or so years ago, when floating point was slow and memory access speeds were not a bottleneck, back then it made sense. On hardware that has software floating point, such as handhelds and certain older consoles, it can also make sense. But on most modern development they are the exception, not the rule.
On a modern desktop CPU --- any x86 processor since about 1997 or so --- the CPU operations are much faster and more accurate than a memory lookup.