To find the values of θ
[tex]\theta\text{ = }\sin ^{-1}1[/tex][tex]\theta\text{ = }\frac{(4n+1)\pi}{2}\text{ for n }\in\text{ Z},\text{ that is, n is an integer}[/tex]Let us pick some values of n, n = ..... -1, 0, 1.....
[tex]\begin{gathered} \theta=\ldots\ldots,\text{ }\frac{-3\pi}{2},\frac{\pi}{2},\frac{5\pi}{2},\ldots\ldots \\ \theta\text{ = }\ldots-270^0,90^0,\text{ 450}^0\ldots\ldots \end{gathered}[/tex]4) Cos θ = 1[tex]\theta=\cos ^{-1}(1)[/tex][tex]\begin{gathered} \theta\text{ = 2n}\pi\text{ where n is an integer} \\ \text{For n = }\ldots.-1,\text{ 0, 1}\ldots.. \\ \theta\text{ = }\ldots\ldots.,\text{-2}\pi,\text{ 0, 2}\pi,\ldots\ldots \\ \theta\text{ = }\ldots.\text{-360}^0,\text{ 0, 36}0^0\ldots. \end{gathered}[/tex]