## OpenStudy9 one year ago What is the Period of the function y=cos (x/5)? I know that the formula for period is 2pi/Absolute value of b.

1. IrishBoy123

here's a way to remember this if you like the normal formulation [in physics\engineering] is $$y = \cos \omega x$$. $$\omega$$ is the angular speed [or angular frequency] measured in radians per second using a simple distance-speed-time formula for angular motion, you can say that $$\omega = \dfrac{2 \pi}{T}$$ where T is the period [for completeness, you can also say that $$\omega = 2 \pi f$$ where fi is the ordinary frequency measured in Hertz ie oscillations per second] so here you have $$\omega = \dfrac{1}{5}$$ and you can now do the rest.....

2. OpenStudy9

so 2pi/1.5 !?

3. IrishBoy123

from $$\omega = \dfrac{2 \pi}{T}$$ you can say $$T = \dfrac{2 \pi}{\omega} = \dfrac{2 \pi}{\frac{1}{5}} = \dots$$