Wednesday

October 22, 2014

October 22, 2014

Posted by **jim** on Monday, January 2, 2012 at 6:44pm.

cos 9 pi

cos 13pi/2

sin(-17 pi0

are all of these undefined?

- pre calc -
**Damon**, Monday, January 2, 2012 at 7:15pmsin 20 pi = sin (2 pi*10) = sin 2pi = 0

cos 9 pi = cos (8 pi +pi). That is 4 times around the circle plus pi so it is really cos (pi) = -1

No, they are not undefined.

**Answer this Question**

**Related Questions**

TRIG! - Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6...

tigonometry - expres the following as sums and differences of sines or cosines ...

Mathematics - Trigonometric Identities - Let y represent theta Prove: 1 + 1/tan^...

Math - 3. find the four angles that define the fourth root of z1=1+ sqrt3*i z...

algebra - Can someone please help me do this problem? That would be great! ...

trig - Reduce the following to the sine or cosine of one angle: (i) sin145*cos75...

pre-cal - Simplify the given expression........? (2sin2x)(cos6x) sin 2x and cos ...

Math - Calculus - The identity below is significant because it relates 3 ...

Math, Pre-Calc - the original problem was: Solve: sin(3x)-sin(x)=cos(2x) so far ...

pre calc trig check my work please - sin x + cos x -------------- = ? sin x sin ...