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Properties of Functions
3 2Sketch the following function 1f x x x x
0 0 1 intercept at 0,1x f y 3 20 0 1y x x x
20 0 1 1 1 1 1
1 or 1 cuts the axis at 1,0 , 1,0
y x x x x x
x x x
2' 3 2 1 0
3 1 1 0
1 at 13
f x x x
x x
SP x x
13
'' 6 2
'' 4 '' 0 hence maximum SP
'' 1 4 '' 0 hence minimum SP
f x x
f f x
f f x
3 2 321 1 1 1 13 3 3 3 3 27
3 2
321 max at ,27
1 1 1 1 1 0 min at 1,0
f
f
Odd FunctionsA function is said to be odd if
for every value in the
domain of The graph is symmetrical under 180 aboutthe origin
f x f x
x
y
y
3y x
even FunctionsA function is said to be even if
for every value in the
domain of The graph is symmetrical under in the axis
f x f x
xreflection
y
y
y
2y x
First derivative test.1. Differentiate2. Set derivative equal to zero3. Use nature table to determine the behaviour of the graph
Second derivative test1. Differentiate2. Set derivative equal to zero3. Find second derivative 4. Substitute x values in to second derivative5. If second derivative is positive, minimum6. If second derivative is negative, maximum7. If second derivative is zero or does not exist, use nature table
An asymptote is a line at which the rational
polynomial in the form of is undefinedf x
h xg x
1yx
1If 0, is undefined, since is not allowed0
x y
0is therefore a vertical asymptotex 10 0 which is also impossibleyx
0 is therefore a horizontal asymptotey
10 , is positivex yx
1, 0 from above is positivex yx
10 , is negativex y
x
1, 0 from below is negativex yx
2
3Sketch the graph of 2
xyx x
2
0 3 3 30 intercept is 0,2 20 0 2
x y y
2
30 0 3 0 intercept is 3,02
xy x xx x
To find any vertical asymptotes, we set the denominator equal to zero
2 2 02 1 0
2 and 1 are vertical asymptotes
x xx x
x x
1.110.9-1.9-2-2.1xy
Non vertical AsymptotesWhat happens to the y value if x tends to infinity
For the degree of the denominator is greater
than the numerator, hence the function tends to zero.
2
32
xyx x
0 is a non vertical asymptote.y
2
3Sketch the graph of 2
xyx x
2
0 3 3 30 intercept is 0,2 20 0 2
x y y
2
30 0 3 0 intercept is 3,02
xy x xx x
To find any vertical asymptotes, we set the denominator equal to zero
2 2 02 1 0
2 and 1 are vertical asymptotes
x xx x
x x
1.110.9-1.9-2-2.1xy
Non vertical AsymptotesWhat happens to the y value if x tends to infinity
For the degree of the denominator is greater
than the numerator, hence the function tends to zero.
2
32
xyx x
0 is a non vertical asymptote.y
2
A function is defined by
2 11
x xf xx
y f x
y f xFind the coordinates off the points wherethe graph crosses the coordinate axes
Find the equation of all vertical and non vertical asymptotes
Find the coordinates of any stationary points, and, if theyexist determine their nature.
y f xSketch the graph of
f x kState the range of values of the constant k such that the equation has no real solution
22 0 0 1 10 10 1 1
f
intercept at 0,1y
222 10 2 1 0
12 1 1 0
1 and 12
x x x xx
x x
x x
1intercept at ,0 and 1,02
x
Vertical Asymptote when1 0 1x x
2
2
2 31 2 1
2 23 13 3
2
xx x x
x xxx
22 31
y xx
2 3x y x 2 3 is a non vertical asymptotey x
0.9 1 1.1xy
x y
x y
122 3 2 3 2 11
y x x xx
22
22 2 1 21
dy xdx x
2
2
2
20 21
2 1 2 0
1 1
1 11 1 21 1 0
x
x
x
xxx
2
23
32
2 2 1
44 11
dy xdxd y xdx x
2
32
40 : 4 0,1 max0 1
d yxdx
2
32
42 : 4 2,9 min2 1
d yxdx
22 2 2 3 9 2,92 1
f SP
20 2 0 3 1 0,10 1
f SP