Use sigma notation to write the following left Riemann sum. Then, evaluate the left Riemann sum using a calculator. f(x)=ex on [0, In 5] with n=15 Write the left Riemann sum using sigma notation. Choose the correct choice below. 15 (k) OA E . (15) e . k=1 15 . ex. Ins 15 k=1 15 OC .(-) (). L In 5 15 k=1 OA 15 OB. k=1 D. (k-1) The left Riemann sum is (Type an integer or decimal rounded to three decimal places as needed.) #11 Use sigma notation to write the following Riemann sum. Then evaluate the Riemann sum using a calculator. The midpoint Riemann sum for f(x) = 4+ cos xx on [0,10] with n=60 116 In 5 Identify the midpoint Riemann sum. Choose the correct answer below. 60 4+ cos k=1 60 k=1 60 In 5 15 OC. 4+ cos k=1 60 4 + cos . In 5 15 4 + cos 2tk- 2xk-x 12 Use a calculator to evaluate the Riemann sum. The midpoint Riemann sum is 0 PLED 1