please help me why it does not work..
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 :=
the Ks are all uppercase or lowercase.....
but why d.a d.b is not corret it should be 0.1 and 0.1
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: