If cos A + cos B = sin C, prove that ∆ABC is right-angled.​

Question

If cos A + cos B = sin C, prove that ∆ABC is right-angled.​

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Elliana 1 month 2021-08-12T18:27:29+00:00 1 Answer 0 views 0

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    2021-08-12T18:28:49+00:00

    Answer:

    cos(A–C)/2 = cosB/2

    (A–C)/2 = B/2.

    A =B+C. …iv

    we know that A+B+C = 180°

    A+A=180° (by iv )

    2A=180°

    A=90°

    since angle A=90°

    it is right angled  …

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