Saturday

December 20, 2014

December 20, 2014

Posted by **BreAnne** on Friday, January 27, 2012 at 6:39pm.

What is sin(13pi/4) ? Explain your thinking.

- trig -
**Damon**, Friday, January 27, 2012 at 7:03pm3 2/3 pi

3 pi ends up at 180 degrees (2 pi + pi)

2/3 pi = 120 degrees

180 + 120 = 300 = 360 - 60

so 60 degrees below x axis in quadrant 4

cos -60 = 1/2

so

cos (11 pi/3) = 1/2

Now you do any more like that.

**Answer this Question**

**Related Questions**

Trig/PreCalc - Teach me how to express 5sqrt3 - 5i in polar form please. I don't...

Trigonometry - Checking my work - Find the sum of the three smallest positive ...

trig - find exact value cos(13pi/15)cos(-pi/5)-sin(13pi/15)sin(-pi/5)

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

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

trig - The expression 4 sin x cos x is equivalent to which of the following? (...

Advance fuctions - write and that is equivalent to each of the following ...

Advance fuctions - write and that is equivalent to each of the following ...

trig - Give exact answers Sin(11pi/8) so this is sin(pi/4+pi/3) sin(pi/4)*cos(pi...

trig - For each expression in column I, choose the expression from column II to ...