@Jarekkk Thats a mistype there the i should be Y(t) i forgot i had changed that due to that reason.

C is the rate of birth rate

D is the natural death rate

N is the total population. N(t)=x(t)+y(t)+z(t) 

Adding the derivatives gives  dN/dt= (c-d)N

@Jarekkk Thats a mistype there the i should be Y(t) i forgot i had changed that due to that reason.

C is the rate of birth rate

D is the natural death rate

N is the total population. N(t)=x(t)+y(t)+z(t) 

Adding the derivatives gives  dN/dt= (c-d)N

@Jarekkk Ive posted an answer as it wouldnt let me reply to this on my laptop i have to use my phone. Strange. 

Xould you see what im doing wrong on the file ive uploaded. If its worked! 

Thanks i really appreciate it.

@Jarekkk Ive posted an answer as it wouldnt let me reply to this on my laptop i have to use my phone. Strange. 

Xould you see what im doing wrong on the file ive uploaded. If its worked! 

Thanks i really appreciate it.

WORKING3.mw

@Jarekkk thats great that thanks! i also wanted to change the equations so that it included birth rates and death rates. I have produced the following yet it doesnt appear to work. Are you able to see what the issue is please?

WORKING3.mw

@Jarekkk thats great that thanks! i also wanted to change the equations so that it included birth rates and death rates. I have produced the following yet it doesnt appear to work. Are you able to see what the issue is please?

@mlb0406 Sorry i spoke to soon ive got them working. Thanks so much.

@mlb0406 Sorry i spoke to soon ive got them working. Thanks so much.

@Jarekkk Thanks for your help, on your sliders did they work? When im moving them it is saying error in DEtools/DEplot/Checkinitial the 'number' option must be specified before initial conditions. 

Thanks

@Jarekkk Thanks for your help, on your sliders did they work? When im moving them it is saying error in DEtools/DEplot/Checkinitial the 'number' option must be specified before initial conditions. 

Thanks

Thanks for your reply. What would the codeing be for that for instance? Bit of a novice with this.

Thanks

Thanks for your reply. What would the codeing be for that for instance? Bit of a novice with this.

Thanks