Question

ل
if cos A = -24/25 and cosB = 3/5 A is in third
quadrant and B is in fourth quadrant
find sin (A+B).​

Answer 1

Answer:

Given cosA = -24/25 And cosB = 3/5 where π <A < 3π/2 And 3π/2 <B < 2π

A is in third quadrant And B is in fourth quadrant.

Here, sine function is negative.

We know that

Then,

(i) Sin(A +B)

We know that sin(A +B) = sinA cosB + cosA sinB

(ii) Cos(A +B)

We know that cos(A +B) = cosA cosB - sinA sinB