Taylor series for the product cos(z)·cosh(z)

[asi123]

Homework Statement

Hey guys.
I need to develop Taylor series for this function (cos(z) * cosh(z)).
I know the Taylor development for cos and the Taylor development for cosh but I have no idea how to combine the two, if it's possible, any idea guys?
And another thing, does it matters if we are talking about the complex field?

Thanks a lot.

Homework Equations

The Attempt at a Solution

 

[rootX]

Homework Statement

Hey guys.
I need to develop Taylor series for this function (cos(z) * cosh(z)).
I know the Taylor development for cos and the Taylor development for cosh but I have no idea how to combine the two, if it's possible, any idea guys?
And another thing, does it matters if we are talking about the complex field?

Thanks a lot.

Homework Equations

The Attempt at a Solution

cosq= (eiq+ e-iq)/2.
coshq= (eq+ e-q)/2.

might help but you image is yet to be approved.

 

[asi123]

cosq= (eiq+ e-iq)/2.
coshq= (eq+ e-q)/2.

might help but you image is yet to be approved.

Oh, I see.
I'll try it.
Thanks a lot.

BTW the image only shows the function "cosz * coshz" and the Taylor series of this two functions.