The functions sin(x), cos(x) and tan(x) are periodic functions.
The value for these functions are:
[tex]\sin (1665)=-0.70710678.=-\frac{1}{\sqrt[]{2}}[/tex][tex]\cos (1665)=-0.70710678\ldots=-\frac{1}{\sqrt[]{2}}[/tex][tex]\tan (1665)=\frac{\sin (1665)}{\cos (1665)}=1[/tex][tex]\sin (1665)=\cos (1665)=-\frac{1}{\sqrt[]{2}}\cdot\frac{\sqrt[]{2}}{\sqrt[]{2}}=-\frac{\sqrt[]{2}}{2}[/tex]Rationalizing the results, we have the previous values for sin (1665) and
cos(1665) = -sqrt(2)/2.
The value for tan(1665) = 1.
