Trigonometry

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If sin A=3/5 and cosB = 24/25 and angle A and angle B are both in quandrant 1. What is sthe exact value of cos (A-B)?

  • Trigonometry -

    cos (A-B) = cosA cosB - sinA sinB

    Note that cosA = 4/5 and sin B = 7/25, which you can prove using
    cos^2 x + sin^2 x = 1

  • Trigonometry -

    117/125

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