limits and continuity

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City University Of Science & Technology 1

City University Of Science & Technology

Limits & Continuity

Presented By:Haroon rasheedImran khan Ahmad yousafFahad noumanHasham zahid

Instructor:

Sir Nadeem Ahmad Sheikh 2

City University Of Science & Technology

Layout of Presentation

Limits • •

Properties of limits• •

One sided limits• Continuity

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City University Of Science & Technology

Limits DefinitionIf f (x) is function of x and c, L are the real number, then

L is the limit of a function f (x) as x approaches c: (x) = L

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City University Of Science & Technology

Example + 3x 7 )Solution: Apply the limits = + 3(-2) 7 = 4 6 7 = 4 13 = 9 Ans

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City University Of Science & Technology

Uses of Limits in Daily Life

Reaction of two Compounds

Conversion of Ice to Water etc.

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City University Of Science & Technology

Properties of limits

If = L & = MSum rule [ f (x) + g (x) ] = L + MQ: + 5x + 7

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City University Of Science & Technology

One-Sided Limit Right Hand LimitLeft Hand Limit

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City University Of Science & Technology

One-Sided Limit Right Hand Limit If x approach to “ a “ through value of x greater then “ a “ we say that x approach through the right and written asX a+0 or X

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City University Of Science & Technology

Left Hand Limit If x approach to “ a “ through value of x less then “ a “ we say that x approach through the left and written asX a 0 or X

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City University Of Science & Technology

Left Hand Limit Right Hand Limit

If L.H.L = R.H.L

Then exist

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City University Of Science & Technology

Example Find f(x) if f (x) = x+1 ; x<=2 = 2x – 3 ; x > 2Sol: L.H.L f(x) = ( X + 1 ) = 2 + 1 = 3R.H.L f(x) = ( 2x - 3 ) = 2(2) - 3 = 1 f(x) f(x) f (x) does not exist

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City University Of Science & Technology

Examplef (x) = |x|/x at x = 1 = -1

= 1

The left and right limits are different, therefore limit does not exist..

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Continuity Definition Example Properties

City University Of Science & Technology

Definition

A function f is continuous at a point x = c if 1. f (c) is defined

2.

3.

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x clim f (x) exists

x clim f (x) f (c)

City University Of Science & Technology

Examplef (x) = x – 1 at x = 2.

i) f(2) = 1ii) iii)

The limit exist! Therefore the function is continuous at x = 2.

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x 2lim x 1 1

x 2f (2) 1 lim x 1

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Check Continuity & Discontinuity

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By definition of  g  g(2) = 3 g(x)=x2 -4/(x-2)

limx → 2 g(x) = limx → 2 (x2 - 4)/(x - 2) =limx → 2 ( x- 2)(x + 2)/(x-2)

Now putting the limiting value = limx → 2 (x + 2) = 4

g(x) is discontinuous because  limx → 2 g(x) ≠ g(2)

City University Of Science & Technology

Continuity Properties If two functions are continuous on the same interval, then their sum, difference, product, and quotient are continuous on the same interval..Every polynomial function is continuous..Every rational function is continuous.. 18

City University Of Science & Technology 19

City University Of Science & Technology

ANY QUESTION ???

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