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Max
Max asked in Science & MathematicsMathematics · 2 years ago

calculus question?

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  • Indikos
    Lv 7
    2 years ago

    y = 4sqrt(4x+5)

    Differentiating wr t dy/dt = 4 * 1/sqrt(4x+5) *4dx/dt

    At (5,20) we have dx/dt = 2

    So dy/dt = 16/(4*5+5) * 2 = 32/25

    Let q be distance from origin

    so q^2 = x^2 + y^2

    Differentiating wr t

    2q dq/dt = 2xdx/dt + 2ydy/dt

    At (5,20) q^2 = 5^2 + 20^2 = 425

    q = sqrt(425)

    So 2sqrt(425) dq/dt = 2*5*2 + 2*20*32/25

    Now solve for dq/dt

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