Question

cos7a+cos3a-cos5a - cosa÷ sin7a-sin3a-sin5a + sina=cot2a​

Answer 1

Answer:

here it is

Step-by-step explanation:

{ ( sin A - sin 7A ) + ( sin 5A -sin 3A ) } / { ( cos A + cos 7A ) - ( cos 5A + cos 3A ) }

= ( -2 sin 3A cos 4A + 2 sin A cos 4A ) / ( 2 cos 4A cos 3A - [ 2 cos 4A cos A ] )

( sin A - sin B = 2 sin (A + B)2 cos (A - B)2)

(cos A - cos B = -2 sin (A + B)2 sin (A - B2))

{cos (- theta )= cos theta and sin (- theta )= sin theta}

= {2 cos 4A [ sin A - sin 3A ] } / { 2 cos 4A [ cos 3A - cos A]}

= { sin A - sin 3A } / { cos 3A - cos A }

= [ -2 sin A cos 2A ] / [ -2 sin 2A sin A ] = cos 2A / sin 2A

= cot 2A

Answer 2

Answer:

2A

Step-by-step explanation:

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