Consider the differential equation   d/dx y(x)=2*y(x)*(y(x)-4), on the rectangle -1 < x < 1, -2 < y < 7.40 in the xy-plane.

(a) Use DEplot to plot the direction field for the differential equation on the given domain. Assign your answer to my_plot_1.

restart: with(DEtools):
DEexp1:=2*y(x)*(y(x)-4);

DE:=Diff(y(x),x)=DEexp1;

DEplot(DE, y(x), x=-1..1, y=-2..7.4);
Error, (in DEtools/DEplot/CheckDE) derivatives must be given explicitly

Thanks for your help!

task:

Use DEplot to sketch a direction field for my_deq and the solution curve for the initial condition T(0) = 88 C. Assign your plot to my_plot.

*Note: my_deq is the differential equation 

My input:

ODE2:=(Diff(T(t), t) = 1/59*(18-T(t)));

DEplot( ODE2, T(t), t=-4..4, {[T(0)=88]}, y=0..100);

Error Received: 

Error, (in DEtools/DEplot/CheckInitial) the 'number' option must be specified before initial conditions

The only thing I can find about this error is the input isn't in the form of a differential equation... But I'm pretty sure it is.

Thanks!