Step-by-step explanation:
A left Riemann sum approximates a definite integral as:

Given ∫₂⁸ cos(x²) dx:
a = 2, b = 8, and f(x) = cos(x²)
Therefore, Δx = 6/n and x = 2 + (6/n) (k − 1).
Plugging into the sum:
∑₁ⁿ cos((2 + (6/n) (k − 1))²) (6/n)
Therefore, the answer is C. Notice that answer D would be a right Riemann sum rather than a left (uses k instead of k−1).
Answer:
110 words in 5 min, 220 words in 10 min
Step-by-step explanation:
y = mx (there is no intercept because you can't type anything in 0 minutes)
66 = 3m
m = 22
y = 22x
5 minutes:
y = 22(5) = 110 words
10 minutes:
y = 22(10) = 220 words
I would say D. It makes the most Since
The answer is 24 square yards
24ft=8yd
9ft=3yd
So 8*3=24 square yard
Hope this helps