Question

If cosA/ cos B. = m and
cos A/ sin B = n

Then show that (m² + n²)Cos² B = n²

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Answer 1

Answer:

hiii dear frd

Step-by-step explanation:

L.H.S= (m2+n2)cos2b

= {(cosa/cosb)2 +(cosa/sinb)2}cos2b

= {(cos2a/cos2b) +(cos2a/sin2b)}cos2b

= (cos2a.sin2b +cos2a.cos2b / cos2b.sin2b)cos2b

= cos2a(sin2b+cos2b) / sin2b

= cos2a / sin2b

R.H.S= n2

=(cosa/sinb)2

= cos2a / sin2b

Therefore, L.H.S=R.H.S

hope this answer helpful u

Answer 2

Answer:

HENCE PROVED..

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