C-09-Q070mediumsingle_mcqIf tanA=1\tan A = 1tanA=1, then 2sinAcosA=?2\sin A \cos A = ?2sinAcosA=?a000b12\dfrac{1}{2}21c111d222ব্যাখ্যাSince A=45∘A = 45^\circA=45∘, both sinA\sin AsinA and cosA\cos AcosA equal 12\dfrac{1}{\sqrt2}21. Therefore 2sinAcosA=2⋅12⋅12=12\sin A\cos A = 2\cdot\dfrac{1}{\sqrt2}\cdot\dfrac{1}{\sqrt2} = 12sinAcosA=2⋅21⋅21=1 (this is also sin2A=sin90∘=1\sin 2A = \sin 90^\circ = 1sin2A=sin90∘=1).