Wednesday

April 16, 2014

April 16, 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

**Related Questions**

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

Pre-Calc Help!!!!!!!! - Evaluate the expression under the given conditions. sin2...

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

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

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

Pre-Calc - Evaluate the expression without using a calculator(show work please...

Pre-calc - Evaluate the trigonometric functions by memory or by contruscting ...

pre calc - Use the sum-to-product formula to simplify the expression: If sin 52...

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

pre calc - evaluate the trigonometric function of the given quadrantal angle. ...