What is the fundamental period of 4sin(21t-1)

Question

From my calculation the fundamental period is $\frac{21\pi}{2 }$ is this correct?

Answer 1

A general form is given by:

$$\text{a}\cdot\sin\left(\omega\cdot t+\varphi\right)\tag1$$

And we know that:

$$\omega=2\pi\text{f}=\frac{2\pi}{\text{T}}\tag2$$

So:

$$\text{a}\cdot\sin\left(\frac{2\pi}{\text{T}}\cdot t+\varphi\right)\tag3$$

So, the period is given by:

$$\text{T}=\frac{2\pi}{\omega}\tag4$$

you're not right!