Calculus: Continuity by: javier AWS

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Calculus: Continuity

by: javier

Calculus: Continuity (continued)

by: javier

Continuity layman definition

Continuity: layman definition

Is this function continous at x = 2 ? □ Can we ’trace’ the graph around x = 2 □ without lifting our pencil □ without running out of ink

6

4

2

0 −4

−2

0

2

4

Continuity: layman definition

Is this function continous at x = 0 ? □ Can we ’trace’ the graph around x = 0 □ without lifting our pencil □ without running out of ink

6

4

2

0 −4

−2

0

2

4

Continuity: layman definition

Is this function continous at x = 0 ? □ Can we ’trace’ the graph around x = 0 □ without lifting our pencil □ without running out of ink

4 3 2 1 0 −4

−2

0

2

4

Continuity: layman definition

Is this function continous at x = 0 ? □ Can we ’trace’ the graph around x = 0 □ without lifting our pencil □ without running out of ink

4 3 2 1 0 −1 −4

−2

0

2

4

Continuity: layman definition

Y

Is this function continous at x = 0 ? □ Can we ’trace’ the graph around x = 0 □ without lifting our pencil □ without running out of ink

y = tan(x)

X

Continuity: layman definition

Is this function continous at x = π2 ? □ Can we ’trace’ the graph around x = □ without lifting our pencil □ without running out of ink

Y

y = tan(x)

X

π 2

Continuity: layman definition

Is this function continous at x = 0 ? □ Can we ’trace’ the graph around x = 0 □ without lifting our pencil □ without running out of ink

1 0.5 0 −0.5 f(x) = sin

−1 −0.5

0

0.5

(1) x

1

Continuity rigorous definition

Continuity: rigorous definition

DEFINITION: f(x) is said to be ”continous at c” IFF? □ limx→c f(x) exists and is finite □ f(c) exists and is finite □ the above two are equal

10

5 f(x) 0

−1

0

1

2

Continuity famous types of discontinuities

Continuity: famous types of discontinuities

DEFINITION: f(x) is said to be ”continous at c” IFF? □ JUMP Discontinuities □ ASYMPTOTE Discontinuities □ REMOVABLE Discontinuities □ OTHER Discontinuities

Continuity famously continous everywhere functions

Continuity: famously continous everywhere functions

some functions that are fmaously continous at every real number: □ polynomials □ sin(x) and cos(x) □ exponential functions, ex □ combinations of these

Continuity what can you do with it

Continuity: what can you do with it

□ many nice things happen when for continous

functions □ continous functions make continous functions when added, multiplied, etc □ continous functions allow limits through

0

−2

f(x)

−4 −1

0

1

2

Continuity: what can you do with it

□ many nice things happen when for continous

functions 0

□ continous functions make continous functions

when added, multiplied, etc □ continous functions allow limits through

−2

√ √ limx→3 x + 1 = limx→3 x + 1

f(x)

−4 −1

0

1

2

Continuity: what can you do with it

functions □ continous functions make continous functions

0

when added, multiplied, etc □ continous functions allow limits through √ √ limx→3 x + 1 = limx→3 x + 1

−2

f(x)

−4 −1

0

1

2

□ many nice things happen when for continous

√ √ limx→−5 x + 1 = limx→−5 x + 1

Continuity: what can you do with it

□ EXREME VALUE THEOREM states that if a

real-valued function f is continuous in the closed and bounded interval [a,b], then f must attain a maximum and a minimum, each at least once.

0

−2

f(x)

−4 −1

0

1

2

Continuity: what can you do with it

□ EXREME VALUE THEOREM states that if a

10

real-valued function f is continuous in the closed and bounded interval [a,b], then f must attain a maximum and a minimum, each at least once.

8 6 4 2 f(x) 0 0

1

2

3

4

Continuity: what can you do with it

□ INTERMEDIATE VALUE THEOREM states that if a

5

continuous function, f, with an interval, [a, b], as its domain, takes values f(a) and f(b) at each end of the interval, then it also takes any value between f(a) and f(b) at some point within the interval.

4 3 2 1 f(x) 0 0

1

2

3

4

Continuity: what can you do with it

□ MEAN VALUE THEOREM is one of the most

important theoretical tools in Calculus. It states that if f(x) is defined and continuous on the interval [a,b] and differentiable on (a,b), then there is at least one number c in the interval (a,b) (that is a < c < b) such that the average rate of change from a to b is equal to the instantanous rate of change at point c

0

−2

f(x)

−4 −1

0

1

2

Continuity: what can you do with it

□ MEAN VALUE THEOREM (ice melting version) 0

−2

f(x)

−4 −1

0

1

2