Let r = usual driving rate
let t = usual driving time
We need to figure out t
The distance she covers in her usual time at her usual rate is r*t
The distance she covers in her new time at her new rate is:
(1+t)*((2/3)r)
Set this equal to each other and solve for t.
rt = (2/3)r + (2/3)rt
(1/3)rt = (2/3)r
(1/3)t = (2/3)
t = 2
So her usual time is 2 hours. (There's probably a faster way to do this)
Plug in n = 1 into the nth term formula
a(n) = 4n-1
a(1) = 4*1-1
a(1) = 3
So the first term is 3
The second term will be 7 because we add on 4 each time, as indicated by the slope of 4. This is also known as the common difference.
So the nth term is found by adding 4 to the (n-1)st term, in other words,
a(n) = a(n-1)+4
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In summary, the answer is
a1=3; an=an-1+4
which is choice B
Answer:
Range = [- 2.5, 0.5] = [ - 5/2, 1/2]
Step-by-step explanation:
Smallest value of cos α = - 1,
largest value of cos α = 1.
When cos 4x = - 1, y=3/2cos4x-1 = 3/2*(-1) - 1 = - 5/2 = - 2 1/2 = - 2.5
When cos 4x = 1, y=3/2cos4x-1 = 3/2*1 - 1 = 1/2 = 0.5
Range = [- 2.5, 0.5] = [ - 5/2, 1/2]
Answer:

Now we can find the limits in order to determine outliers like this:


So for this case the left boundary would be 3, if a value is lower than 3 we consider this observation as an outlier
b. 3
Step-by-step explanation:
For this case we have the following summary:
represent the minimum value
represent the first quartile
represent the median
represent the third quartil
represent the maximum
If we use the 1.5 IQR we need to find first the interquartile range defined as:

Now we can find the limits in order to determine outliers like this:


So for this case the left boundary would be 3, if a value is lower than 3 we consider this observation as an outlier
b. 3
Answer:

And when we apply the limit we got that:

Step-by-step explanation:
Assuming this complete problem: "The following formula for the sum of the cubes of the first n integers is proved in Appendix E. Use it to evaluate the limit . 1^3+2^3+3^3+...+n^3=[n(n+1)/2]^2"
We have the following formula in order to find the sum of cubes:

We can express this formula like this:
![\lim_{n\to\infty} \sum_{n=1}^{\infty}i^3 =\lim_{n\to\infty} [\frac{n(n+1)}{2}]^2](https://tex.z-dn.net/?f=%20%5Clim_%7Bn%5Cto%5Cinfty%7D%20%5Csum_%7Bn%3D1%7D%5E%7B%5Cinfty%7Di%5E3%20%3D%5Clim_%7Bn%5Cto%5Cinfty%7D%20%5B%5Cfrac%7Bn%28n%2B1%29%7D%7B2%7D%5D%5E2)
And using this property we need to proof that: 1^3+2^3+3^3+...+n^3=[n(n+1)/2]^2
![\lim_{n\to\infty} [\frac{n(n+1)}{2}]^2](https://tex.z-dn.net/?f=%20%5Clim_%7Bn%5Cto%5Cinfty%7D%20%5B%5Cfrac%7Bn%28n%2B1%29%7D%7B2%7D%5D%5E2)
If we operate and we take out the 1/4 as a factor we got this:

We can cancel
and we got

We can reorder the terms like this:

We can do some algebra and we got:

We can solve the square and we got:

And when we apply the limit we got that:
