I'll attempt problem 1.

(1) I divide the numerator and denominator by n which yields

(2) There's a formula if a>0, then

(3) Since

from (1), I use u-substitution. I let u =

(4) By u substitution the integral becomes

. Edit:No, this is not correct. Scratch this.

(5) Applying the formula (2) with (4) with get

(6) As for the limit,

For problem 3, I believe there's a typo.

should it be

?

I'm sure I have to use the Squeezing Principle for this. I can't seem to integrate sin(x)/x in terms of elementary functions. I'm guessing I can integrate this using the Taylor series for the sine function, but I have no idea after that.