1. ## limits quest

lim x^4-1 / x-1
x-1

the answer is 4 but i donno how so if anyone could tell me i'd appreciate it.

2. What you need is a good factorization

$x^4-1=(x^2-1)\cdot{(x^2+1)}=(x-1)\cdot{(x+1)}\cdot{(x^2+1)}$

Then $\lim_{x\rightarrow{1}}{\frac{x^4-1}{x-1}}=\lim_{x\rightarrow{1}}{\frac{(x-1)\cdot{(x+1)}\cdot{(x^2+1)}}{x-1}}=\lim_{x\rightarrow{1}}{(x+1)\cdot{(x^2+1)}}=4$

3. thx aloooot