Q2 of 90 Page 7

If SinA = 12/13 And sinB = 4/5, where π/2<A < π And 0 <B < π/2, find the following:

(i) sin(A +B) (ii) cos(A +B)

Given sinA = 12/13 And sinB = 4/5 where π/2 <A < π And 0 <B < π/2


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





More from this chapter

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1

If sinA = 4/5 And cosB = 5/13, where 0 <A, B < π/2, find the values of the following:

(i) sin(A +B)


(ii) cos(A +B)


(iii) sin(A –B)


(iv) cos(A -B)

 2

If sinA = 3/5, cosB = –12/13, where A And B Both lie in second quadrant, find the value of sin(A +B).

 3

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)

 4

If tanA = 3/4, cosB = 9/41, where π<A < 3π/2 And 0 <B < π/2, find tan(A +B).