Processing Math: Done

From Förberedande kurs i matematik 1

If we write the angle 67 as

67=66+=+6

we see that the angle 76 on the unit circle is in the third quadrant and makes an angle 6 with the negative x-axis.

Geometrically, tan(76) is defined as the slope of the line having an angle 76 and, because this line has the same slope as the line having angle 6, we have that

tan67=tan6=sin6cos6=2123=13.