Question

If tan2A*tanA = 1 then what is the value of cos2A

Answer 1

hi friend,

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tan2AtanA=2tan²A/1-tan²A=1

→2tan²A=1-tan²A

→3tan²A=1

→A=30

now, cos2A=cos2(30)=cos60=1/2

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I hope this will help u :)