$\sqrt{2}$ = 6/x
limx→∞(1+1/x)^(x+2)
lim(2+1/n)^(n+1)^2
ab+ac+b2
what is the fifth triangular number?
y'+xe^(-x/2)=0
what is the 243rd triangular number
2x^2 + 7x +3
sum from 0 to k-1 of (t/k*v^(t/k))
what is the 243rd triangle number