# Mathematical function with input not in definition

I have just come across a definition for a mathematical function where in the input is not part of the function definition.

This is a simplified variation of the function:

$f(x) = \sin(a) + b$

Therefore, if $x$ is not used the calculation of the result, can I still inverse this function to find $x$ for some $\sin(a) + b$?

• Double check the function definition, this is unlikely. – Yves Daoust Nov 6 '15 at 15:02
• Hi @YvesDaoust, I've double checked, and I'm afraid that this is what's written on the question sheet I have. – user287585 Nov 6 '15 at 15:04
• Have they defined $a$ and $b$ anywhere else? – Element118 Nov 6 '15 at 15:05
• Mh, you should have said it was a homework, I would have commented differently. – Yves Daoust Nov 6 '15 at 15:06
• @Element118, they have not, I think it's mean't to be the lengths of two sides of a right angled triangle: math2.org/math/algebra/functions/trig. – user287585 Nov 6 '15 at 15:08

## 1 Answer

No, you can't invert this function.

• ... because it's not one-to-one. – Rick Decker Nov 6 '15 at 15:16