1. in the general equation $\displaystyle y= acos kx$ the period is determined by the value of x

2. in the general equation $\displaystyle y= acos k(x+b)$ the phase shift is determined by the value of b

3. the period of the function $\displaystyle y= 3cos \frac{2}{3} x-4$ is -4

4. if \theta is in standard position, and 0 <or equal $\displaystyle \theta$ <or equal $\displaystyle 2\pi$, if $\displaystyle sin\theta=\frac{3}{5}$ the value of tan $\displaystyle \theta$ is $\displaystyle \frac{4}{3}$

5. the equation of a sine function with amplitude 4 and period of $\displaystyle 90^o$ is $\displaystyle y=4sin90x$