pls solve this sum needed fastly .. I will mark u as the brainliest
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Step-by-step explanation:
replace θ by A
LHS
cos3A+sin3A/cosA-sinA
=4cos³A-3cosA+3sinA-4sin³A/ cosA-sinA
=4(cos³A-sin³A)-3(cosA-sinA)/(cosA-sinA)
=4(cos³A-sin³A)/cosA-sinA- 3(cosA-sinA)/cosA-sinA
=4(cosA-sinA)(cos²A+cosAsinA+sin²A) -3
=4(1+sinAcosA)-3
=1+4sinAcosA
=1+2.2sinAcosA
=1+2sin2A
=RHS
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