Math, asked by Sheruu, 1 year ago

If tanA =n tanB and sinA= m sinB prove that

cos 2 A= m2-1 / n2-1

Answers

Answered by pnkyashrajp5y1i5

Hope this will help you.....

Attachments:

Sheruu: cheated from xam idea 10th mathematics

pnkyashrajp5y1i5: Achha to tum hi bata do doosra tarika.

pnkyashrajp5y1i5: Babu janta hai 3 months. se maths ka book hath tak nhi lagaye hai.

Sheruu: mujhe kya yaad 3 months se maths ni pdi tene

Sheruu: babu kon

pnkyashrajp5y1i5: Ha to thik hai n tum hi bata do doosre tarike se banake

Sheruu: kese bheju

pnkyashrajp5y1i5: Hmko aur kisko

Sheruu: how

Answered by chintalasujat

Answer:

Step-by-step explanation:

tanθ+sinθ=m and tanθ-sinθ=n

∴, m²-n²

=(m+n)(m-n)

=(tanθ+sinθ+tanθ-sinθ)(tanθ+sinθ-tanθ+sinθ)

=(2tanθ)(2sinθ)

=4tanθsinθ

4√mn

=4√(tanθ+sinθ)(tanθ-sinθ)

=4√(tan²θ-sin²θ)

=4√{(sin²θ/cos²θ)-sin²θ}

=4√sin²θ{(1/cos²θ)-1}

=4sinθ√{(1-cos²θ)/cos²θ}

=4sinθ√(sin²θ/cos²θ)

=4sinθ√tan²θ

=4sinθtanθ

∴, LHS=RHS (Proved)

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