Hello folks,

I am not a math major, so please forgive me if my terminology is not precisely correct. I also selected Geometry and Calculus groups for lack of a Trig option.

To better understand what is happening in a problem requiring a graphing calculator (which I do not own), I am trying to plot data to show a given damped harmonic against some limits to determine the points of intersection of those limits.

I have attached a screen cap of the given information for clarity.

Wolfram Alpha displays the base equation beautifully, but experimentation on how to word the addition of limits eludes me.

I'm hoping someone's experience can help me figure this out?

WA correctly interprets the base harmonic equation: y=e^(-x/5) cos(2pix)

Mathlabs wants me to determine at what t the harmonic exists between -0.4 and 0.4

From there I hit a wall. Please help?

Thanks in advance!