Page 86 - Math SL HB Sem 1
P. 86
CIRCULAR FUNCTIONS AND TR]GONOMETRY
Example: Express (a) 40" in radians
5zr
(b) radians in degrees
6
Lcngth of an arc
ln a unit circle, the length ofan arc subtended by an angle of d radians is d units.
Y
o r)
( rl
cix
figure 3
When enlarged by a factor of r, the arc lenglh becomes rd units.
:
s: arc AB rg
figure 4
4-2
