Thursday

November 27, 2014

November 27, 2014

Posted by **Anonymous** on Tuesday, November 13, 2012 at 2:06pm.

- math -
**Steve**, Tuesday, November 13, 2012 at 2:28pmluckily, you have nice easy 3-4-5 and 5-12-13 triangles.

cosx = -4/5

siny = 5/13

sin(x+y) = (3/5)(-12/13) + (-4/5)(5/13) = -56/65

reasonable, since (x+y) will be in QIII or QIV

**Answer this Question**

**Related Questions**

maths - if sinx=3/5,cosy=12/13,where x and y both lie in 2nd quadrant, find the ...

calc - what is the derivative of sinx- cosy = 0 in its simplest form? I got to ...

trig - find the exact value given that cosA=(1/3) in quad I, sin B=(-1/2) in ...

trig - find the exact value given that cosA=(1/3) in quad I, sin B=(-1/2) in ...

trig - find the exact value given that cosA=(1/3) in quad I, sin B=(-1/2) in ...

Pre-calculus - If cosx=4/5, cosy=12/13 in Quad. IV, find sin(x+y)

Pre-calculus - If cosx=4/5, cosy=12/13 in Quad. IV, find sin(x+y)

Trig - given that sinx=3/4 and cosy=-5/13 and both x and y are in quadrant II, ...

Math - Draw a pair of quadrilaterals where the 1st quad. is congruent to the 2nd...

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