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Math Help - Graphing the period of a trig function.

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    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?
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    Hello kmjt
    Quote Originally Posted by kmjt View Post
    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 \pi built in to your formula for y, so just label the x-axis with integer values. For instance, when x = 5, 0.2\pi x = \pi, so y = 0. And when x = 2.5, 0.2\pi x = \pi/2, so y = 1.5 (the maximum value). And a complete cycle will be between x = 0 and x = 10.

    Grandad
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