Respuesta :

[tex]\begin{gathered} \text{ Recall that} \\ \sin 0=0,\text{ and }\cos 0=1 \\ \text{ The identity} \\ \sin ^2\theta+\cos ^2\theta=1 \\ \text{ when }\theta=0,\text{ is true for } \\ (0)^2+(1)^2=1 \end{gathered}[/tex]