Mathematica Real Part in Mathematica: How to Extract the Real Values from Fractions

[member 428835]

Hi PF!

I have some variables that are all real, and I have a few $i$s, all in a fraction. When I ask Mathematica to give me the real part of the entire fraction, $Re[]$, it simply echoes my input, not giving me anything useful. Any help is greatly appreciated.

 

[phyzguy]

Can you post the code?

 

[member 428835]

 

[member 428835]

Last line is output

 

[Dale]

Looks fine to me. Apparently the expression doesn’t simplify much

 

[phyzguy]

You could try using ComplexExpand:

 

[member 428835]

You could try using ComplexExpand:
View attachment 221008

Yea I've tried this before. I should have been more specific: see what I want is the real component without any imaginary numbers. Like multiplying by the conjugate and simplifying. Do you know if there a built in function that does this?

 

[phyzguy]

Yea I've tried this before. I should have been more specific: see what I want is the real component without any imaginary numbers. Like multiplying by the conjugate and simplifying. Do you know if there a built in function that does this?

Look again at my post. That's what ComplexExpand does. There are no "i's" in the final answer.

 

[member 428835]

Look again at my post. That's what ComplexExpand does. There are no "i's" in the final answer.

Ohhhhh shooot, sorry! I saw the variable $\lambda i$ and thought there was an $i$ in the solution. Sorry and thanks!