Thursday

March 5, 2015

March 5, 2015

Posted by **anna** on Saturday, November 1, 2008 at 2:54am.

inverse sin (-rad2/2)=-45 degrees

I dont understand why cos is 135

- trig -
**Damon**, Saturday, November 1, 2008 at 10:40amfor the cosine = -sqrt 2/2 negative x axis

means quadrant 2 or quadrant 3

It could be either 180 + 45 or 180 - 45

so either 135 or 225

for the sine = -sqrt 2/2

means quadrant 3 or quadrant 4

that is 180 + 45 or 360 - 45

so either 225 or 315

225 satisfies both the sine and the cosine.

**Answer this Question**

**Related Questions**

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

trigonometry (please double check this) - Solve the following trig equations. ...

Math - Trying to understand an inverse trig function. Evaluate Cos^-1 (sqr3/2) ...

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

Trig - What is the exact value of cos 40 degrees cos 50 degrees minus sin 40 ...

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

Trigonometry - Please review and tell me if i did something wrong. Find the ...

inverse - If f(x)=cosx + 3 how do I find f inverse(1)? Thanks y = cos(x) + 3 the...

Precal - I do not understand how to do this problem ((sin^3 A + cos^3 A)/(sin A...

trig - Evaluate sin(29 degrees)cos(31 degrees) + cos(29 degrees)sin(31 degrees) ...