biggest problem for me in cal is that everything was explained through regular variables and then it assumes you automatically know how to apply it to trig.
one session my TA said
"i know how to do the problem but i dont know how to explain it in english. ill get back to you in a week." only problem was that the homework was due the next day...that was the last time i went to a TA session
and i nearly gave up on cal all together.
i was taking other classes i enjoyed more like astronomy, economics and partying, so it was really hard to get pumped up about having to open the cal book and put so much time into it. i figured it out eventually though.