When identifying a sinusoidal function, you may use the basic shape of either the sine curve or the cosine curve – one is just a horizontal transformation of the other!

The curve in the figure above can take the equation or .

Use the applet to view the four basic shapes.

## Exercise 1:

It has been noted above that . In other words, if you slide the cosine function 90 units to the right, your curve can be expressed as the sine function.

In a similar way, complete:

When a curve takes one of these four basic shapes shown in the applet, we can avoid using a horizontal transformation.

## Exercise 2:

Reproduce the following graphs on geogebra; using only functions of the form or (that is, no horizontal translation). Remember to use the degree symbol . A pc shortcut is ALT O; a mac short cut is SHIFT OPTION 8.

Graph 1:

Graph 2:

Graph 3:

Graph 4:

Graph 5:

Graph 6:

Go to Trigonometric Functions Menu