You've not learned that all of the constraints have to come after the "given" statement? Where is "Find"?
Go read the help files about how to set up a solve block!
Or are you just dumping on this forum?
i have a question so only i want to find d.1 d.2.
all variables are a constant value.
so do I have to change d.a=0.1 not :=
If ALL of your used variables have to be constant (even q=100) and you only want to vary d1 and d2m then you are asking for the impossible. There is a linear relationship between d1 and d2 and to fulfill your equation at least one of the two must be negative. So they can't be both in the range from 0 to 0.3.
HOW about this one?
q is not constant value.
This is exactly what MFra already had shown quite a while ago.
If q is variable, too, you have a myriad number of solutions. And if you chose a q value for which a solution exists, there usually exist an infinite number of additional solution for d1 and d2.
So you have some additional degrees of freedom.
q=10, d1=0.1, d2=0.121
q=10, d1=0.15, d2=0.071
q=10, d1=0.2, d2=0,021
Here is the formula where you can calculate d2 if q and d1 are given: