If k is a constant, you can try :
1. Let :
2. Partial fraction by first factoring the denominator
1) I want to understand how you got that expression in your first helper.
2) I have done partial fraction decomposition before, but I don't understand what you're saying "factoring the denominator"
I'm sorry, I'm really having trouble understanding.
It's because I want to use trigonometry identity :I want to understand how you got that expression in your first helper
Using will change the denominator to :
In fact, you also can use : because it will be relevant to identity :
If the question turns out to be , you can use substitution : because it is relevant to identity :
For the second one, follow Mr. F suggestion :