Hi All, Could any one please help me solve this.

I have big expression with sin(x) and cos(x), which resulted after integrating another function. I need to apply the in the following expression(F).

F =

Where are given as follows:

Infact they are the electric fields in two different waveguides a, b. However, The expressions are similar .

I need to use the following representation of the Dirac delta function;

Now, I need to show that the function F, after the limit applied is equal to :

Please I need help to get this done. I would be grateful for the help.