My math teacher speaks like a college professor teaching a Mathematical Analysis course and many of the students (including me) find it hard to follow along. Once a student asked him rather bravely what the application of a power series would be to a question and he just had this "Why the heck are you even asking me this, isn't it obvious" look. Any tips to deal with this?
The ideal would be if students in the class could support each other. In the example you described, after student A asks about the application of a power series, and the teacher makes the unpleasant face, it could be helpful if student B said, "I'm wondering about that too."
Consider that the teacher might make a face because he's embarrassed that he didn't explain things more clearly. Who knows!
You may want to let the department leader know how things are going, and request that s/he sit in on the class, to form a direct opinion.
Consider also that sometimes people with poor social skills excel in their field, and display an astonishing ability to alienate or offend people.
In short, don't take it as a measure of your own abilities. Just let it wash off like water off a duck's back. Make sure you ask one or more questions each week. By asking questions, you'll get more comfortable asking questions, and the teacher will get more used to people asking questions.
If you don't understand something, do check what your textbook has to say; but also, you may ask, for example:
I'm not clear about (topic).
Could you explain where such-and-so comes from, in a different way? OR: Is there a way of looking at this that would help it feel less abstract? etc.