Answer:
an = 115 + (n - 1) (-6)
a25 = - 29
Step-by-step explanation:
We use the definition for the nth term of an arithmetic sequence:
an = a1 + (n - 1) d
a5 = 91 = a1 + (5 - 1) d
91 = a1 + 4 d
a20 = 1 = a1 + (20 - 1) d = a1 + 19 d
1 = a1 + 19 d
now we subtract term by term one expression from the other
90 = 4 d - 19 d
90 = - 15 d
divide both sides by -15 to isolate d
d = 90 / (-15) = -6
Now we can calculate what a1 is using for example:
1 = a1 + 19 d
1 = a1 - 114
add 114 to both sides:
115 = a1
Then our general expression for the sequence is:
an = 115 + (n - 1) (-6)
We can now use it to calculate the value of a25:
a25 = 115 + (24) * (-6) = -29
We can write it like this:

if x isn't 0, we can divide both sides by x:

and again

and now we can calcuate

and divide both sides by 4.
We're left with 9!!
so the solution is 9!
well, we know the sine, and we also know that we're on the II Quadrant, let's recall that on the II Quadrant sine is positive whilst cosine is negative.
![\bf sin^2(\theta)+cos^2(\theta)=1~\hspace{10em} tan(\theta )=\cfrac{sin(\theta )}{cos(\theta )} \\\\[-0.35em] ~\dotfill\\\\ sin^2(a)+cos^2(a)=1\implies cos^2(a) = 1-sin^2(a) \\\\\\ cos^2(a) = 1-[sin(a)]^2\implies cos^2(a) = 1-\left( \cfrac{3}{4} \right)^2\implies cos^2(a) = 1-\cfrac{3^2}{4^2} \\\\\\ cos^2(a) = 1-\cfrac{9}{16}\implies cos^2(a) = \cfrac{7}{16}\implies cos(a)=\pm\sqrt{\cfrac{7}{16}}](https://tex.z-dn.net/?f=%5Cbf%20sin%5E2%28%5Ctheta%29%2Bcos%5E2%28%5Ctheta%29%3D1~%5Chspace%7B10em%7D%20tan%28%5Ctheta%20%29%3D%5Ccfrac%7Bsin%28%5Ctheta%20%29%7D%7Bcos%28%5Ctheta%20%29%7D%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20sin%5E2%28a%29%2Bcos%5E2%28a%29%3D1%5Cimplies%20cos%5E2%28a%29%20%3D%201-sin%5E2%28a%29%20%5C%5C%5C%5C%5C%5C%20cos%5E2%28a%29%20%3D%201-%5Bsin%28a%29%5D%5E2%5Cimplies%20cos%5E2%28a%29%20%3D%201-%5Cleft%28%20%5Ccfrac%7B3%7D%7B4%7D%20%5Cright%29%5E2%5Cimplies%20cos%5E2%28a%29%20%3D%201-%5Ccfrac%7B3%5E2%7D%7B4%5E2%7D%20%5C%5C%5C%5C%5C%5C%20cos%5E2%28a%29%20%3D%201-%5Ccfrac%7B9%7D%7B16%7D%5Cimplies%20cos%5E2%28a%29%20%3D%20%5Ccfrac%7B7%7D%7B16%7D%5Cimplies%20cos%28a%29%3D%5Cpm%5Csqrt%7B%5Ccfrac%7B7%7D%7B16%7D%7D)
![\bf cos(a)=\pm\cfrac{\sqrt{7}}{\sqrt{16}}\implies cos(a)=\pm\cfrac{\sqrt{7}}{4}\implies \stackrel{\textit{on the II Quadrant}}{cos(a)=-\cfrac{\sqrt{7}}{4}}\\\\[-0.35em]~\dotfill\\\\tan(a)=\cfrac{sin(a)}{cos(a)}\implies tan(a)=\cfrac{~~\frac{3}{4}~~}{-\frac{\sqrt{7}}{4}}\implies tan(a)=\cfrac{3}{4}\cdot \cfrac{4}{-\sqrt{7}}\\\\\\tan(a)=-\cfrac{3}{\sqrt{7}}\implies \stackrel{\textit{rounded up}}{tan(a) = -1.13}](https://tex.z-dn.net/?f=%5Cbf%20cos%28a%29%3D%5Cpm%5Ccfrac%7B%5Csqrt%7B7%7D%7D%7B%5Csqrt%7B16%7D%7D%5Cimplies%20cos%28a%29%3D%5Cpm%5Ccfrac%7B%5Csqrt%7B7%7D%7D%7B4%7D%5Cimplies%20%5Cstackrel%7B%5Ctextit%7Bon%20the%20II%20Quadrant%7D%7D%7Bcos%28a%29%3D-%5Ccfrac%7B%5Csqrt%7B7%7D%7D%7B4%7D%7D%5C%5C%5C%5C%5B-0.35em%5D~%5Cdotfill%5C%5C%5C%5Ctan%28a%29%3D%5Ccfrac%7Bsin%28a%29%7D%7Bcos%28a%29%7D%5Cimplies%20tan%28a%29%3D%5Ccfrac%7B~~%5Cfrac%7B3%7D%7B4%7D~~%7D%7B-%5Cfrac%7B%5Csqrt%7B7%7D%7D%7B4%7D%7D%5Cimplies%20tan%28a%29%3D%5Ccfrac%7B3%7D%7B4%7D%5Ccdot%20%5Ccfrac%7B4%7D%7B-%5Csqrt%7B7%7D%7D%5C%5C%5C%5C%5C%5Ctan%28a%29%3D-%5Ccfrac%7B3%7D%7B%5Csqrt%7B7%7D%7D%5Cimplies%20%5Cstackrel%7B%5Ctextit%7Brounded%20up%7D%7D%7Btan%28a%29%20%3D%20-1.13%7D)
Answer:
Its D) Africa has more users than the Middle East but fewer users than North America.
Step-by-step explanation:
correct for Edge2020