Hi,I'm a beginner.

here's the example:

f[x_] := E^(I*x)

Conjugate[f[x]]*f[x]

I'd like get 1,but it give me a complex function coz it regard x as complex.

please help me:how to claim x is real?

by the way,is that necessary to define a letter as a constant.no matter yes or not,how to refer a letter constant to be real or pure imaginary

Thank you!

here's the example:

f[x_] := E^(I*x)

Conjugate[f[x]]*f[x]

I'd like get 1,but it give me a complex function coz it regard x as complex.

please help me:how to claim x is real?

by the way,is that necessary to define a letter as a constant.no matter yes or not,how to refer a letter constant to be real or pure imaginary

Thank you!

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