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# Core 2 math help?

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Y = x^-3 + 48x
Find the equation of the two tangents parallel to the x-axis
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2. (Original post by Bhansongal98)

Y = x^-3 + 48x
Find the equation of the two tangents parallel to the x-axis
Differentiate, set the derivative equal to zero and solve the quadratic. That'll give you two points at which the gradient is 0 and hence the tangent parallel to the x-axis. Then you form your equation by doing y - y_1 = m(x-x_1) where you find y_1 by plugging x_1 into your equation of the curve.

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