Equations of Tangents and Normals to the Curve y=f(x)
Equations of Tangents and Normals to the Curve y=f(x)
Equations of Tangents to the Curve y=f(x)
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Tangent to a curve at a point is a straight line that just touches the curve at that point.
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The slope of the tangent to the curve y=f(x) at a point x=a is given by f’(a), the derivative of f(x) evaluated at x=a.
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The equation of this tangent line can be found using the point-slope form of the equation of a line, which is given by y - y1 = m(x - x1), where (x1, y1) is a point on the line and m is the slope. In the context of a curve y=f(x), x1=a, y1=f(a), and m=f’(a).
Equations of Normals to the Curve y=f(x)
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A normal to a curve at a point is a straight line perpendicular to the tangent at that point.
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The slope of the normal to the curve y=f(x) at a point a is the negative reciprocal of the slope of the tangent at that point, i.e., -1/f’(a).
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The equation of the normal can also be found using the point-slope form of the equation of a line. For a normal, x1=a, y1=f(a) and m=-1/f’(a).
General Tips
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It is crucial to find the correct derivative of the function, as it gives the slope of the tangent.
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The negative reciprocal of the derivative at a given point will provide the slope of the normal.
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Practice applying the techniques to various functions and values of x to become comfortable with deriving equations of tangents and normals.
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When checking your work, ensure that the tangent touches the curve at the given point and the normal is perpendicular to the tangent.
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Don’t forget to give your final answer in the form of an equation i.e., y=mx+c. Use the appropriate details from your workings to replace m, x and c.
By understanding and mastering these concepts, you’ll be able to confidently determine equations of tangents and normals for various functions.