1 00:00:00,000 --> 00:00:05,000 Most solvers available on the market do not accept the differential equation in this form-- 2 00:00:05,000 --> 00:00:09,000 the second-order differential equation, which is not an explicit form. 3 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. 4 00:00:16,000 --> 00:00:22,000 The trick is to turn this differential equation into two differential equations of first order. 5 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 6 00:00:28,000 --> 00:00:34,000 is some new variable called y, and now you have to provide the second equation 7 00:00:34,000 --> 00:00:36,000 for the derivative of y with respect to time. 8 00:00:36,000 --> 00:00:44,000 Should that be 7-3y+4x or 7-3 times the derivative of x plus 4x 9 00:00:44,000 --> 99:59:59,999 or 1/37 minus the second derivative plus 4x or 1/37 minus the first derivative of y plus 4x.