## Trigonometry 7th Edition

The equation is not an identity. A counterexample: $\theta=0.$
Graphing utility used: online calculator, desmos.com. (see below) The graphs of the two expressions are not equal, implying that the equation is not an identity. A counterexample is $\theta=0$, for which LHS=undefined (cot0 is undefined) RHS=$\displaystyle \frac{0+1}{1}=1$ LHS$\neq$RHS, so the equation is not an identity