Please answer question no 12 in the attached file - Maths - Vector Algebra

Question

Please answer question no 12 in the attached file

Neha Sethi · Accepted Answer

Dear student a) sinθ2=12a^-b^We have:a^-b^2=a^-b^ a^-b^ as a→ a→=a→2⇒a^-b^2=a^ a^-a^ b^-b^ a^+b^ b^⇒a^-b^2=a^2-2a^ b^+b^2 as a^ b^=b^ a^⇒a^-b^2=a^2-2a^b^cosθ+b^2 as a^ b^=a^b^cosθ ⇒a^-b^2=2-2cosθ asa^= b^=1⇒a^-b^2=21-cosθ=22sin2θ2=4sin2θ2⇒sin2θ2=14a^-b^2⇒sinθ2=12a^-b^Hence proved

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