Wednesday

October 1, 2014

October 1, 2014

Posted by **Amanda** on Thursday, April 19, 2012 at 12:22pm.

sin (A+B); tan A= 12/5, A in quadrant 3, sin B= -3sqrt(10)/10, B in quadrant 4.

- Pre-Calc Help!!!!!!!! -
**Steve**, Thursday, April 19, 2012 at 12:33pmin QIII, sin and cos are both negative.

You have a 5-12-13 triangle, so

sinA = -12/13

cosA = -5/13

in QIV, cos is positive.

You have a 3-1-√10 triangle, so

cosB = 1/√10

Now apply the addition formula

sin(A+B) = sinAcosB + cosAsinB

**Answer this Question**

**Related Questions**

Pre-Calc Help - Evaluate the expression under the given conditions. (show work ...

Pre-Calculus - Evaluate the expression under the given conditions.? show work ...

pre-calc helpppp - Evaluate the expression under the given conditions (show ...

Pre-Calc help NOW PLEASE!!! - Evaluate the expression under the given conditions...

Pre-calc help please!!! - 1) tan(sin^-1(5/6)-cos^-1(1/7) 2) tan(è + ); cos...

Trig - Find cos(s+t) if cos s= -1/2 and sin t= 3/5, s and t are in quadrant II. ...

trig - how do i set this problem up? Find tan (s + t) given that sin s = 1/4, ...

pre-calculus - Write the first expression in terms of the second if the terminal...

pre calc - Find the exact value of sin(x-y) if sinx=-3/5 in Quadrant III and ...

Trig - How do i set this trig problem up? PLEASE help me. Find tan (s + t) given...