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Summary of differentiation rules

Given two functions, f ( x ) and g ( X ) we know that:

d d x b = 0
d d x ( x n ) = n x n - 1
d d x ( k f ) = k d f d x
d d x ( f + g ) = d f d x + d g d x

Rules of differentiation

  1. Find f ' ( x ) if f ( x ) = x 2 - 5 x + 6 x - 2 .
  2. Find f ' ( y ) if f ( y ) = y .
  3. Find f ' ( z ) if f ( z ) = ( z - 1 ) ( z + 1 ) .
  4. Determine d y d x if y = x 3 + 2 x - 3 x .
  5. Determine the derivative of y = x 3 + 1 3 x 3 .

Applying differentiation to draw graphs

Thus far we have learnt about how to differentiate various functions, but I am sure that you are beginning to ask, What is the point of learning about derivatives? Well, we know one important fact about a derivative: it is a gradient. So, any problems involving the calculations of gradients or rates of change can use derivatives. One simple application is to draw graphs of functions by firstly determine the gradients of straight lines and secondly to determine the turning points of the graph.

Finding equations of tangents to curves

In "Average Gradient and Gradient at a Point" we saw that finding the gradient of a tangent to a curve is the same as finding the gradient (or slope) of the same curve at the point of the tangent. We also saw that the gradient of a function at a point is just its derivative.

Since we have the gradient of the tangent and the point on the curve through which the tangent passes, we can find the equation of the tangent.

Find the equation of the tangent to the curve y = x 2 at the point (1,1) and draw both functions.

  1. We are required to determine the equation of the tangent to the curve defined by y = x 2 at the point (1,1). The tangent is a straight line and we can find the equation by using derivatives to find the gradient of the straight line. Then we will have the gradient and one point on the line, so we can find the equation using: y - y 1 = m ( x - x 1 ) from grade 11 Coordinate Geometry.

  2. Using our rules of differentiation we get: y ' = 2 x

  3. In order to determine the gradient at the point (1,1), we substitute the x -value into the equation for the derivative. So, y ' at x = 1 is: m = 2 ( 1 ) = 2

  4. y - y 1 = m ( x - x 1 ) y - 1 = ( 2 ) ( x - 1 ) y = 2 x - 2 + 1 y = 2 x - 1
  5. The equation of the tangent to the curve defined by y = x 2 at the point (1,1) is y = 2 x - 1 .

Curve sketching

Differentiation can be used to sketch the graphs of functions, by helping determine the turning points. We know that if a graph is increasing on an interval and reaches a turning point, then the graph will start decreasing after the turning point. The turning point is also known as a stationary point because the gradient at a turning point is 0. We can then use this information to calculate turning points, by calculating the points at which the derivative of a function is 0.

If x = a is a turning point of f ( x ) , then: f ' ( a ) = 0 This means that the derivative is 0 at a turning point.

Take the graph of y = x 2 as an example. We know that the graph of this function has a turning point at (0,0), but we can use the derivative of the function: y ' = 2 x and set it equal to 0 to find the x -value for which the graph has a turning point.

Questions & Answers

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Eke Reply
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Missy Reply
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Lale Reply
no can't
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Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
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Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
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Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
has a lot of application modern world
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Crow Reply
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RAW Reply
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I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
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what is the stm
Brian Reply
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industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
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What is STMs full form?
scanning tunneling microscope
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Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
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Source:  OpenStax, Siyavula textbooks: grade 12 maths. OpenStax CNX. Aug 03, 2011 Download for free at http://cnx.org/content/col11242/1.2
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