How can I find the angle between the 3d vector & x-axis ?

[@ADAMS@]

Hello :- My name is Anas I'm a new member in this forum .

I have a small question

what is the angle between the vector 3i +j-4k and the x-axis ?

and please explain me what is the method of answer this question

Im sorry , I know I have many mistakes in this topic because my English language is poor

Thank you , and I wish from you to answer me very fast

 

[Integral]

Tell us what you know about the Dot product of 2 vectors.

 

[@ADAMS@]

I Didnt know about this
Im sorry

 

[Integral]

Maybe you know it as the http://en.wikipedia.org/wiki/Dot_product"