How do I graph this function: y = 4 * cos (x + π/3)?

Answer 1

desmos has a good function plotter.

Just go to desmos dot com and click START graphing.

then input this function y = 4 * cos ( x + pi/3) into the input box and it will graph it for you

You know the graph of cosine.

So this function shifts to the left 60 degrees or pi/3 but scaled by a factor of 4. So it is 4 times as fat

ALso, you can create a little table

Here's some data

Answer 2

The amplitude is 4 (the number in front). This means the wave will go up 4 and down 4 from its center (total distance of 8 from min to max). The cosine normally starts at its maximum point, right? The phase shift is the tricky part! That + pi/3 means that you're going to slide that thang to the left by pi/3. I would divide my pi up into thirds (not so hard to eyeball if you had to). Then sliiiiiiiiiiiiide to the left.