some help with early advanced calc questions #1

i appreciate any and all help. im gettin further and further into this and im gettin more and more lost(Thinking)...im not very good at writing notation on the computer, but i tried my best...i think most is pretty self explanatory, but sq() means square root...

say what limit theorem you use and compute the limit

1. lim as t goes to 0...(sin 2t + t^2cos 5t)

2. lim as x goes to 0 from negatives...sq(x^2)/x

3. lim as x goes to pi over 2...sin (cos(x))/cosx

4. lim as x goes to 0....(1- sq(1+x) -sq(1-x))/x

thanks in advanse for any help, answers, or explanations