- #1

Psi137

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- TL;DR Summary
- trigonometric function, composite function

Recently I debated with a friend of mine, and the topic was 'Is it reasonable that we call 2(sinx) as trigonometric function?'.

My friend said that if we can call y=2(sinx) as trigonometric function, we can call y=x as trigonometric too, because if we call the former 'correct', there is no reason that we shouldn't call y=arcsin(sinx) as trigonometric function.

Generally, in encyclopedia, it defines trigonometric function for only 6 types, sin, cos, tan, csc, sec, cot.

Then, here is total conclusion :

If y=f(x) is trigonometric function, can y=g(f(x)) be called trigonometric function?

My friend said that if we can call y=2(sinx) as trigonometric function, we can call y=x as trigonometric too, because if we call the former 'correct', there is no reason that we shouldn't call y=arcsin(sinx) as trigonometric function.

Generally, in encyclopedia, it defines trigonometric function for only 6 types, sin, cos, tan, csc, sec, cot.

Then, here is total conclusion :

If y=f(x) is trigonometric function, can y=g(f(x)) be called trigonometric function?