Investigation into combined transoformations of 6 trigonometric functions

Authors Avatar

Keval Chauhan

Maths Core Three
Investigation of combined transformations

A line has the general formula of, the part in brackets must always be there the others are variables, and may not be there in some equations for a line.

Y= at(bx+c)+d

T, can be any trigonometric function (Sine, cosine, tangent, secant, cosecant or cotangent.)

Below is a picture that shows each of the 6 trigonometric functions.

A is a stretch in the y-axis.
B can give a stretch in the x-axis which can change the frequency of a graph. If b is greater than 1 there will be an increased frequency, but if b is less than 1 there will be a lower frequency.
C translates f(x) by c if c is +ve(positive) the graph will shift to the right by c, if c was –ve(negative) the graph will shift to the left by c.
D is a translation in the y-axis, if d is +ve the graph will shift up, but if d is -ve the graph will shift down.

In this investigation I will be looking at combined transformations with 2 transformations max per equation. There are 6 possible combinations by 4C2(nCr).

These possible combinations are

ab, ac, ad, bc, bd, cd. I will also be studying the symmetry, maximum/minimum points and asymptotes of each graph.

The first transformation combination I will be looking at is ab using the trigonometric function of sine. Sine is shown by a blue line in Figure 1.0

A sine graph has no asymptotes but has a rotational symmetry or 180o about the origin(0,0), therefore the only remaining thing to look at is the maximum and minimum values.

y=asin(bx)

I am going to change a and b to the following values

Join now!

Predictions

Graph 1 – Has a maximum of 1 by point (0.5π,1) and a minimum of -1 at the points
(-0.5π, -1)

Graph 2 – I expect this graph to have a maximum at (0.25π, 2) and a minimum at
(-0.25π,-2)

Graph 3 – I expect this graph to have a maximum at (-0.25π,2) and a minimum at
(0.25π,-2)

Graph 4 – I expect this graph to have a maximum at (-0.25π,2) and a minimum at
(0.25π,-2)

Graph 5 – I expect this graph to have a maximum at (0.25π, 2) and a minimum at
(-0.25π,-2)

Results

Graph 1

Graph 2       ...

This is a preview of the whole essay