# Thread: How do i make a sine function from a graph?

1. ## How do i make a sine function from a graph?

I was given a graph, and i assigned an axis and plotted points. i have the max, min, principal axis, amplitude, and period but i dont know now how to make a function in A sin B(x-c) + D form.
Maximum - 6.45
Minimum - 1.00
Principal axis - 3.725
amplitude - 2.725
Period - 9.2

I uploaded a not exact picture of the graph, its the blue line.

2. ## General Sine Function

Hello mathnerd501

Welcome to Math Help Forum!
Originally Posted by mathnerd501
I was given a graph, and i assigned an axis and plotted points. i have the max, min, principal axis, amplitude, and period but i dont know now how to make a function in A sin B(x-c) + D form.
Maximum - 6.45
Minimum - 1.00
Principal axis - 3.725
amplitude - 2.725
Period - 9.2

I uploaded a not exact picture of the graph, its the blue line.
For the function $A\sin B(x-C)+D$:
The amplitude is $A$ (assuming $A > 0$)

The maximum value is $D+A$

The minimum value is $D-A$

The period is $\frac{2\pi}{B}$

The principal axis is where $x = C$
If you plug in the values that you've been given, you should be able to write down (or easily work out) all the values. Can you do this OK?