Question

Given that sinA =a/b then cosA is equal to
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Answer 1

Given

SinA=a/b

on squring both side

Sin^2 A = (a/b)^2

cos^2A ,= 1 - (a/b)^2

cosA = sqrt( b^2 - a^2)/b

Answer 2

Answer:

√ (b2-a2)/b

Step-by-step explanation:

According to the question,

Sin θ =a/b

We know,

Sin2 θ +cos2 θ =1

Sin2 A = 1-cos2 A

Sin A = √ (1-cos2 A

So,

Cos θ = √ (1-a2/ b2) = √ ((b2-a2)/b2) = √ (b2-a2)/b

Hence,

cos θ = √ (b2 – a2)/b