Hi everyone.
Im trying to calculate the det of the Jacobian however i keep getting this error.
Just what exactly does "scalar value" mean in mathcad? And more importantly, what can i assign u and v to fix this?
In my problem both u ∈ [0,2π] and v ∈ [0,π] but i dont know how to assign these values in mathcad.
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Then see this, its your initial Mathcad file. Nothing I changed. You defined in a wrong way the Jacobian matrix...
Post your Mathcad file...
Here is an example:
Thank you. But can you explain to me why it works for you,but it dosent for me? I dont see any difference at the first glance,other then everything being re arranged.
Then see this, its your initial Mathcad file. Nothing I changed. You defined in a wrong way the Jacobian matrix...
Oh i see, thank you. The problem is that i dont know how to define partial derivatives in mathcad. Is this also why i cant calculate the surface area of a bohemian dome?
@Cornel wrote:
Then see this, its your initial Mathcad file. Nothing I changed.
Sure you did (apart from correcting the Jacobian definition)!
You change the definition of u and v from ranges to simple scalars. Otherwise you would get the very same error message with the expression in the last line.
Apart from the correct definition of the derivatives in the Jacobian, the main "trick" is this:
Making the determinant a function dependent on r, u and v. Otherwise Prime tries to use the ranges which you defined at the top and fails with the error message you had seen.
BTW, I would do without the u- and v-ranges and use CreateMesh for plotting the sphere:
and ... you could create a vector function and use the built-in "Jacob" function:
Its not necessary to evaluate symbolically, but it sure makes sense, I guess.
@Werner_E wrote:
@Cornel wrote:
Then see this, its your initial Mathcad file. Nothing I changed.
Sure you did (apart from correcting the Jacobian definition)!
You change the definition of u and v from ranges to simple scalars. Otherwise you would get the very same error message with the expression in the last line.
Yes, true. I didn't notice because from the beginning u and v were changed below in worksheet to scalars by MN guy. If u and v are changed to simple scalars then we can use:
Otherwise, if u and v are range variables then we need to use what also Werner said, DJ(r, u, v):
Oh, wow,I completely missed those too. Its unreal how much trouble one tiny oversight can create. Also i had no idea you can just do everything with vectors.
Thank you.