kill(all)$

van=facebook.com/LearningCalculus$

encircle(x) := x^2 - 1$
uncircle(x) := sqrt(x + 1)$

triangle(x):=uncircle(x*(x+2))$ triangle(x);

sum: 0$

for x: 1 thru 20 do
(
    sum: sum + encircle(x) + triangle(x)
)$

sum;