Thread: Graphing the period of a trig function.

I'm a bit confused. I know that to calculate the period you do 2pi/k but what if the question says y=1.5sin0.2pi x?

2pi/0.2pi = 2/0.2 = 10

How do I know where 10 is on a trig graph? I label my graph with pi/2, pi, 3pi/2, 2pi, etc. If there is no pi in the period how do I know where it would be on a graph?

Hello kmjt

Originally Posted by kmjt

I'm a bit confused. I know that to calculate the period you do 2pi/k but what if the question says y=1.5sin0.2pi x?

2pi/0.2pi = 2/0.2 = 10

How do I know where 10 is on a trig graph? I label my graph with pi/2, pi, 3pi/2, 2pi, etc. If there is no pi in the period how do I know where it would be on a graph?

Then don't label it like that! You have built in to your formula for , so just label the -axis with integer values. For instance, when , so . And when , so (the maximum value). And a complete cycle will be between and .

Grandad

Thanks