How do I find the equation of a cosine function with a maximum of 3, a minimum of -3, and a period of 4?

Guest May 6, 2017

#1**+1 **

How do I find the equation of a cosine function with a maximum of 3, a minimum of -3, and a period of 4?

lets see

y=3cos b(x+c)

c can be any constant becasue you have not mentioned phase shift.

where period = 2pi/b

\(\frac{2\pi}{b}=4\\ \frac{\pi}{b}=2\\ b=\frac{\pi}{2}\)

so it is

\(y=3cos[\frac{\pi }{2}(x+c)]\)

check (here is your graph )

Melody
May 6, 2017

#2**+1 **

This is what you must remember.

\(y=a*cos[b(x+c)]+d\\~\\ \text{a is the amplitude}\\ \text{d is the vertical shift}\\ \text{c is the horizontal, or phase, shift}\\ \text{and last but not least, the period is}\frac{2\pi}{b}\\ \text{The angle is in radians}\\ \)

If you remember that then these questions become almost trivia.

Sine functions work the same way.

Melody
May 6, 2017