How do I solve the equation dy/dt = 2y - 10dydt=2y10?

1 Answer
Jan 31, 2015

You can use a technique known as Separation of Variables.
Take all the yy to one side and the tt on the other...
You get:

dy/(2y-10)=dtdy2y10=dt

Now you can integrate both sides with respect to the correspondent variables:

int1/(2y-10)dy=intdt12y10dy=dt
int1/(2(y-5))dy=intdt12(y5)dy=dt

And finally
1/2ln(y-5)=t+c12ln(y5)=t+c

Now you can express yy as:
ln(y-5)=2t+cln(y5)=2t+c
y-5=c_1e^(2t)y5=c1e2t where c_1=e^cc1=ec
y=c_1e^(2t)+5y=c1e2t+5

You can substitute back to check your result (calculating dy/dtdydt) remembering that now it is: y=c_1e^(2t)+5y=c1e2t+5