WEBVTT
00:00:00.000 --> 00:00:05.000
Most solvers available on the market do not accept the differential equation in this form--
00:00:05.000 --> 00:00:09.000
the second-order differential equation, which is not an explicit form.
00:00:09.000 --> 00:00:16.000
What you instead have to provide is a function that returns the first derivative, the rate of change.
00:00:16.000 --> 00:00:22.000
The trick is to turn this differential equation into two differential equations of first order.
00:00:22.000 --> 00:00:28.000
Here is a hint for you--the first equation should be that the derivative of x with respect to time
00:00:28.000 --> 00:00:34.000
is some new variable called y, and now you have to provide the second equation
00:00:34.000 --> 00:00:36.000
for the derivative of y with respect to time.
00:00:36.000 --> 00:00:44.000
Should that be 7-3*y+4*x or 7-3 times the derivative of x plus 4x
00:00:44.000 --> 99:59:59.999
or 1/3*7 minus the second derivative plus 4*x or 1/3*7 minus the first derivative of y plus 4*x.