9.125 E10 is the same as 9.125 × 10¹⁰ in standard form.
Ok so the first one is
1.x=135
2.x=-23
3.x=3
4.x=70
Answer:
-4
Step-by-step explanation:
Go to x value of -5 and go down until you touch line.
20 times 5 is 100. We can multiply 2*5 and get 10, then add another zero to make it easier.
Split up the interval [2, 5] into
![n](https://tex.z-dn.net/?f=n)
equally spaced subintervals, then consider the value of
![f(x)](https://tex.z-dn.net/?f=f%28x%29)
at the right endpoint of each subinterval.
The length of the interval is
![5-2=3](https://tex.z-dn.net/?f=5-2%3D3)
, so the length of each subinterval would be
![\dfrac3n](https://tex.z-dn.net/?f=%5Cdfrac3n)
. This means the first rectangle's height would be taken to be
![x^2](https://tex.z-dn.net/?f=x%5E2)
when
![x=2+\dfrac3n](https://tex.z-dn.net/?f=x%3D2%2B%5Cdfrac3n)
, so that the height is
![\left(2+\dfrac3n\right)^2](https://tex.z-dn.net/?f=%5Cleft%282%2B%5Cdfrac3n%5Cright%29%5E2)
, and its base would have length
![\dfrac{3k}n](https://tex.z-dn.net/?f=%5Cdfrac%7B3k%7Dn)
. So the area under
![x^2](https://tex.z-dn.net/?f=x%5E2)
over the first subinterval is
![\left(2+\dfrac3n\right)^2\dfrac3n](https://tex.z-dn.net/?f=%5Cleft%282%2B%5Cdfrac3n%5Cright%29%5E2%5Cdfrac3n)
.
Continuing in this fashion, the area under
![x^2](https://tex.z-dn.net/?f=x%5E2)
over the
![k](https://tex.z-dn.net/?f=k)
th subinterval is approximated by
![\left(2+\dfrac{3k}n\right)^2\dfrac{3k}n](https://tex.z-dn.net/?f=%5Cleft%282%2B%5Cdfrac%7B3k%7Dn%5Cright%29%5E2%5Cdfrac%7B3k%7Dn)
, and so the Riemann approximation to the definite integral is
![\displaystyle\sum_{k=1}^n\left(2+\frac{3k}n\right)^2\frac{3k}n](https://tex.z-dn.net/?f=%5Cdisplaystyle%5Csum_%7Bk%3D1%7D%5En%5Cleft%282%2B%5Cfrac%7B3k%7Dn%5Cright%29%5E2%5Cfrac%7B3k%7Dn)
and its value is given exactly by taking
![n\to\infty](https://tex.z-dn.net/?f=n%5Cto%5Cinfty)
. So the answer is D (and the value of the integral is exactly 39).