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(cos5A+cos3A+cosA)/(sin5A-sin3A+sinA)=...


`(cos5A+cos3A+cosA)/(sin5A-sin3A+sinA)=`

A

cotA

B

tanA

C

sinA

D

CosA

Text Solution

Verified by Experts

The correct Answer is:
A
LHS `=(cos5A+cosA+cosA)(sin5A-sin3A+sinA)`
`=(2cos(5A+3A)/2. cos(5A-3A)/(2)+cosA)/(2cos(5A+3A)/2.cos(5A-3A)/(2)+sinA)`
`=(2cos4AcosA+cosA)/(2cos4AsinA+sinA)`
`=(cosA(2cos4A+1))/(sinA(2cos4A+1))=cotA`=RHS Hence Proved.
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