no cosa= las cossais, then kind

1.	no cosa= las cossais, then kind
Answer» Given Equation is cosa = 12/13. We know that sin^2a + cos^2a = 1 sin^2a + (12/13)^2 = 1 sin^2a + 144/169 = 1 sin^2a = 1 - 144/169 sin^2a = 25/169 sin a = 5/13. Now, cos^2b + sin^2b = 1 cos^2b + (4/5)^2 = 1 cos^2b + 16/25 = 1 cos^2b = 1 - 16/25 cos^2b = 9/25 cosb = 3/5. We know that sin(a + b) = sin a cosb + sin b cosa = (5/13) * (3/5) + (4/5) * (12/13)

Answer»

Given Equation is cosa = 12/13.

We know that sin^2a + cos^2a = 1

sin^2a + (12/13)^2 = 1

sin^2a + 144/169 = 1

sin^2a = 1 - 144/169

sin^2a = 25/169

sin a = 5/13.

Now,

cos^2b + sin^2b = 1

cos^2b + (4/5)^2 = 1

cos^2b + 16/25 = 1

cos^2b = 1 - 16/25

cos^2b = 9/25

cosb = 3/5.

We know that sin(a + b) = sin a cosb + sin b cosa

= (5/13) * (3/5) + (4/5) * (12/13)

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