Hi,
1)27pi/2
: sin (13pi + pi/2)
=1
so cos=0
2)11pi/2
:sin(5pi + pi/2)
=1
so cos=0
i used the unit circle to figure this out
Thanks
What you've written is non-sense. Sine and cosine are often used in mathematics in ways that have nothing to do with angles.
Sine and cosine are commonly introduced in basic trigonometry courses but you should have learned other definitions, that, again, have nothing to do with angles, in, say, secondary school.