(1 point) Use a trigonometric substitution to simplify the following indefinite integral, but do not evaluate it. (Use t as your new variable.) 81 - 2 de = dt\f(1 point) A. Estimate , 4/(1 + x2) dax by subdividing the interval into 8 parts, using (i) the left Riemann sum: ( 4/(1 + x?) do = (ii) the right Riemann sum: So 4/(1 + x? ) de ~ (iii) the trapezoid rule S, 4/(1 + x? ) da zSo -5 (1 point) Calculate each of the following approximations for dr. (:| 1) LEFT(2) = RIGHT(2) = TRAP(2) = MID(2) =