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PROGRAMME 8. DIFFERENTIATION APPLICATIONS . Programme 8: Differentiation applications . Equation of a straight line Tangents and normals to a curve at a given point Maximum and minimum values Points of inflexion. Programme 8: Differentiation applications . Equation of a straight line
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PROGRAMME 8 DIFFERENTIATION APPLICATIONS
Programme 8: Differentiation applications Equation of a straight line Tangents and normals to a curve at a given point Maximum and minimum values Points of inflexion
Programme 8: Differentiation applications Equation of a straight line Tangents and normals to a curve at a given point Maximum and minimum values Points of inflexion
Programme 8: Differentiation applications Equation of a straight line (1) The basic equation of a straight line is: where:
Programme 8: Differentiation applications Equation of a straight line How about the equation of the line? Found it.
Programme 8: Differentiation applications Equation of a straight line (2) Given the gradient m of a straight line and one point (x1, y1) through which it passes, the equation can be used in the form: Example:
Programme 8: Differentiation applications Equation of a straight line Exercise 1 Found the equation of the straight line of: Line passing through (2, -3), gradient -2. Line passing through (5, 3), gradient 2.
Programme 8: Differentiation applications Answers: 1 2.
Programme 8: Differentiation applications Equation of a straight line (3) If the gradient of a straight line is m and the gradient of a second straight line is m1 where the two lines are mutually perpendicular then:
Programme 8: Differentiation applications Exercise A point P has coordinates (4,3) and the gradient m of straight line through P is 2. Then there is a line perpendicularly through P. Found the equation of the line. Answer
Programme 8: Differentiation applications Are these two straight line perpendicular each other?
Programme 8: Differentiation applications Exercise 2
Programme 8: Differentiation applications Further Example 1. 2.
Programme 8: Differentiation applications Answer (1)
Programme 8: Differentiation applications Answer (2)
Programme 8: Differentiation applications Equation of a straight line Tangents and normals to a curve at a given point Maximum and minimum values Points of inflexion
Programme 8: Differentiation applications Tangents and normals to a curve at a given point Tangent The gradient of a curve, y = f (x), at a point P with coordinates (x1, y1) is given by the derivative of y (the gradient of the tangent) at the point: The equation of the tangent can then be found from the equation:
Programme 8: Differentiation applications Tangents and normals to a curve at a given point Example
Programme 8: Differentiation applications Tangents and normals to a curve at a given point Normal The gradient of a curve, y = f (x), at a point P with coordinates (x1, y1) is given by the derivative of y (the gradient of the tangent) at the point: The equation of the normal (perpendicular to the tangent) can then be found from the equation:
Programme 8: Differentiation applications Tangents and normals to a curve at a given point Example Found the normal of the last exercise!
Programme 8: Differentiation applications 1 Tangents and normals to a curve at a given point Exercise
Programme 8: Differentiation applications 1 Equation of a straight line Tangents and normals to a curve at a given point Maximum and minimum values Points of inflexion
Programme 9: Differentiation applications Maximum and minimum values A stationary point is a point on the graph of a function y = f (x) where the rate of change is zero. That is where: This can occur at a local maximum, a local minimum or a point of inflexion. Solving this equation will locate the stationary points.
Programme 9: Differentiation applications Maximum and minimum values Having located a stationary point it is necessary to identify it. If, at the stationary point
Programme 9: Differentiation applications Maximum and minimum values If, at the stationary point The stationary point may be: a local maximum, a local minimum or a point of inflexion The test is to look at the values of y a little to the left and a little to the right of the stationary point
Programme 8: Differentiation applications Equation of a straight line Tangents and normals to a curve at a given point Maximum and minimum values Points of inflexion
Programme 9: Differentiation applications Points of inflexion A point of inflexion can also occur at points other than stationary points. A point of inflexion is a point where the direction of bending changes – from a right-hand bend to a left-hand bend or vice versa.
Programme 9: Differentiation applications Points of inflexion At a point of inflexion the second derivative is zero. However, the converse is not necessarily true because the second derivative can be zero at points other than points of inflexion.
Programme 9: Differentiation applications Points of inflexion The test is the behaviour of the second derivative as we move through the point. If, at a point P on a curve: and the sign of the second derivative changes as x increases from values to the left of P to values to the right of P, the point is a point of inflexion.