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Ankh asked in Science & MathematicsMathematics · 10 months ago

The curve y = ax 2 + bx + c passes through the point (2, 28) and is tangent to the line at the origin. Find a, b, and c.?

Calculas1 

3 Answers

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  • 10 months ago

    Do you mean "and its tangent at that point passes through the origin", and "Calculus"?

  • Tangent to what line at the origin?

    28 = 4a + 2b + c

    It passes through the origin, too

    0 = 0a + 0b + c

    0 = c

    28 = 4a + 2b

    14 = 2a + b

    b = 14 - 2a

    y = ax^2 + bx + c

    y = ax^2 + (14 - 2a) * x + 0

    y = ax^2 + (14 - 2a) * x

    Assuming it's tangent to y = 0 at (0 , 0)

    y' = 2ax + (14 - 2a)

    y' = 0 when x = 0

    0 = 2a * 0 + 14 - 2a

    0 = 14 - 2a

    0 = 7 - a

    a = 7

    y = ax^2 + (14 - 2a) * x

    y = 7x^2 + (14 - 14) * x

    y = 7x^2 + 0x

    y = 7x^2

  • 10 months ago

    The question mentions a line that is tangent to the curve at the origin, but gives none of the necessary details about that line, like its slope.

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