Understanding Periods of Trigonometric Functions with Different Frequencies

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The period of the function f(x) = sin 3x - (1/2)sin x is determined by the least common multiple of the individual periods of the sine functions involved. The period of sin 3x is 2π/3, while the period of sin x is 2π. Since 2π is a multiple of 2π/3, the overall period of the combined function is 2π. Understanding this concept is crucial for analyzing trigonometric functions with different frequencies. The key takeaway is that the period of the resulting function is dictated by the greater period among the components.
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f(x)= sin 3x - (1/2)sin x, find the period.

i know the period for sin 3x is 2pi/3 and the period of sin x is 2pi but how do you subtract these? I totally forget how to do this! I mean i could find the answer with any graphing program but i want to know how to do this type of problem.
 
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asatru jesus said:
f(x)= sin 3x - (1/2)sin x, find the period.

i know the period for sin 3x is 2pi/3 and the period of sin x is 2pi but how do you subtract these? I totally forget how to do this! I mean i could find the answer with any graphing program but i want to know how to do this type of problem.

Go with the greater value (period). Can you see why?
 
Why subtract them? The two functions will both repeat when you reach the least common multiple of their separate periods. Here, it should be obvious that 2\pi is a multiple of \frac{2\pi}{3}.
 
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