If cosA = – 24/25 And cosB = 3/5, where π <A < 3π/2 And 3π/2 <B < 2π, find the following:
(i) sin(A +B) (ii) cos(A +B)
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
(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