3.23.3 Can you answer these questions?

3.23.3.1 How to find a value to make function positive and real?

http://mathematica.stackexchange.com/questions/132883/how-to-find-a-value-to-make-function-positive-and-real

 
Let 
 
x=(((-3 + r) r^2 + a^2 (1 + r)) Csc[])/(a (-1 + r)) 
 
y=Sqrt[(a^2 (a^2 (1 + r)^2 + 2 r^2 (-3 + r^2)) + 
a^4 (-1 + r)^2 Cos[]^2 - ((-3 + r) r^2 + 
a^2 (1 + r))^2 Csc[]^2)/(a^2 (-1 + r)^2)] 
 
...
 

- asked by MrDi 1vote

3.23.3.2 Creating an automatic code feedback for class

http://mathematica.stackexchange.com/questions/132880/creating-an-automatic-code-feedback-for-class

 
I'm trying to create a server application that accepts uploaded Mathematica files (that follow a certain API), then run a few tests on modules defined within those files. This is for a course where  ...
 

- asked by michael99man 1vote

3.23.3.3 Nontrivial background removal

http://mathematica.stackexchange.com/questions/132844/nontrivial-background-removal

 
I have an image of a product on a poorly made green screen and need to segment out just the product: 
 
 
 
The problem is that it contains a mirror, so simple color-based methods are not enough. 
 
I tried  ...
 

- asked by M.R. 4votes

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