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if ( cos A + cos B )/( sin A + sin B...

if ` ( cos A + cos B )/( sin A + sin B ) = k ( (sin A - sin B)/ ( cos A- cos B))` then k is

A

1

B

2

C

`1/2`

D

`-1`

Text Solution

Verified by Experts

The correct Answer is:
D
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NEW JOYTHI PUBLICATION-TRIGONOMETRIC FUNCTIONS-EXERCISE
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  19. cos A .cos (120^@ +A ) . Cos (120 ^@ -A ) is

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