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The Toolkit Functions.

These are also called the "elementary functions."  A partial list is given in section 2.5.

  1. Constant
  2. Linear or Identity Function.
  3. Absolute Value.
  4. Quadratic.
  5. Cubic.
  6. Square Root.
  7. Cube Root.
  8. Reciprocal.
  9. Sine Function.
  10. Exponential.
Name and Definition Graph Domain and Range Important Points and Comments
Constant

c(x) = 1

D: { x | x Î Ñ }

R: { y | y = 1 }

All horizontal lines are classified as constants.

Even function.

Linear or Identity Function

f(x) = x

D: { x | x Î Ñ }

R: { y | y Î Ñ }

Goes thru the origin (0,0)

Odd function

Absolute Value

g(x) = | x |

D: { x | x Î Ñ }

R: { y | y ³ 0 }

Goes thru the origin (0,0)

Even function

 

Quadratic

h(x) = x^2

D: { x | x Î Ñ }

R: { y | y ³ 0 }

Goes thru the origin (0,0), (1,1), and (-1,1)

Even function

 

Cubic

m(x) = x^3

D: { x | x Î Ñ }

R: { y | y Î Ñ }

Goes thru the origin (0,0), (1,1), and (-1,-1)

Odd function

 

Square Root

n(x) = x^(1/2)

D: { x | x ³ 0 }

R: { y | y ³ 0 }

Goes thru the origin (0,0) and (1,1)

No symmetry

Cube Root

p(x) = x^(1/3)

D: { x | x Î Ñ }

R: { y | y Î Ñ }

Goes thru the origin (0,0), (1,1), and (-1,-1)

Odd function

 

Reciprocal

r(x) = 1/x

D: { x | x ³ 0 or x £ 0 }

R: { y | y ³ 0 or y £ 0 }

 

Goes thru the origin (0,0), (1,1), and (-1,-1)

Odd function

Horizontal asymptote at y = 0

Vertical asymptote at x = 0

 

Sine Function

s(x) = sin(x)

D: { x | x Î Ñ }

R: { y | -1 £ y £ 1 }

Goes thru the origin (0,0)

Odd function

Sine is 2*pi periodic

Exponential

t(x) = 2^x

D: { x | x Î Ñ }

R: { y | y > 0 }

Goes thru the origin (0,0), (1,2), and (-1,1/2).

No symmetry

Horizontal asymptote at y = 0

The general exponential b^x, b>0 and not b = 1 goes thru (1,b) and (-1,1/b). 

The case where 0 < b < 1 gives a graph similar to 2^x except reflected about the y axis.

 

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  last modified September 05, 2007