can someone please explain what "lim" means? and that weird E thing next to the latex? cuz i always see these and i dont know what they are.
"lim" is short for limit. It means take the limit, so, for example \(\lim_{x\rightarrow 0}(x^2-3)\) means take the limit of the expression x2 - 3 as x goes to zero.
The "weird E thing" is the summation sign (it's the Greek upper case letter sigma), so for example \(\sum_{k=1}^3x_k\) is the same thing as x1 + x2 + x3.