# help with Laplace transform of tangent function

#### korean

##### New member
hey does anyone know what the Laplace transformation of tangent is??
im having trouble finding it. i dont need the whole proof of it i just simply need to know what it is to finish my original problem.

ps i didnt know if i should post here or the adv. math forums because this question can be put in both....depending on the way you look at it....so ill just put it in both cuz someone looking in here and not there might know the answer.

#### tkhunny

##### Moderator
Staff member
Isn't there a continuity problem?

p.s. Bad idea. Generally, visitors are the same.

#### stapel

##### Super Moderator
Staff member
Note: Other copy of this question deleted.

#### korean

##### New member
umm ok so your saying that the laplace transformation of tangent does not exist?? because the tangent function is discontinous??

#### tkhunny

##### Moderator
Staff member
No, not quite.

We have a definition for continuous f(t) defined for t>0, provided the limit exists.

We have a definition for f(t) piecewise continuous for t>0, with a finite number of discontinuities, provided the limit of the last piece exists.

I'm not seeing a definition for an infinite number of discontinuities.

#### korean

##### New member
ok you lost me here??? can you give me an example??? or something??

#### tkhunny

##### Moderator
Staff member
I'm just looking at the definition of the Laplace Transform. Have you a book?

#### daon

##### Senior Member
L(tan(t)) = $$\displaystyle \L \int^{oo}_0 e^{-st}tan(t)dt$$

Have fun