Question

PreCalculus Question: y=-4-cosπx graphing help?

Answer 1

What kind of graphing calc do you have?

Answer 2

If you've already graphed it, set your window to....
-5.25<x<5.25
-7.39<y<7.39

Answer 3

\[y = A\cos\left(k(x-h)\right) + B\]
Amplitude is A
period is 2pi/k
phase shift is h
average is B
You graph should be a cosine function, flipped on the x-axis, shifted down 4, and have a period of 2. Since there is no change in amplitude (other than the flip) the graph will range between -5 and -3 on the y-axis. Since there is not a phase shift, start with 0. Divide the period into 4 equal parts at x = 0, 0.5, 1, 1.5, 2. Then evaluate the function at these values.
\[\begin{array}{c|c}
x &y\\
\hline
0&-5\quad \text{ (lowest point)}\\
0.5&-4\quad \text{(average)}\\
1&-3\quad \text{ (highest point)}\\
1.5&-4\quad \text{(average)}\\
2&-5\quad \text{ (lowest point)}\\
\end{array}\]