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__

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__

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