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    Hi,
    I'd appreciate any help on this question.

    f(A)= cosA/1+sinA + 1+sinA/cosA

    Prove that f(A)=2secA

    I cross multiplied and attempted to put under common denominator,but i could'nt get final ans.Is this the right method?Can anyone help!!!!

    Sukh.
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    (Original post by sukh_b)
    Hi,
    I'd appreciate any help on this question.

    f(A)= cosA/1+sinA + 1+sinA/cosA

    Prove that f(A)=2secA

    I cross multiplied and attempted to put under common denominator,but i could'nt get final ans.Is this the right method?Can anyone help!!!!

    Sukh.

    Yeh it is right. Just work through it again.
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    f(A) = cosA/1+sinA + 1+sinA/cosA
    f(A) = (cos^2A + 1 + 2sinA + sin^2A)/cosA(1 + sinA)

    But cos^2A + sin^2A = 1, so

    f(A) = (2 + 2sinA)/cosA(1 + sinA)
    f(A) = 2(1 + sinA)/cosA(1 + sinA)
    f(A) = 2/cosA = 2secA as required
    • Thread Starter
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    Cheers people.

    I made the mistake on squishy's 3rd step.I didnt simplify.

    Thanks again.

    Sukh.
 
 
 
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