## anonymous one year ago (FAN AND MEDAL) help please!!!

1. AaronAndyson

Question?

2. anonymous

Ben shared his post with 2 friends. Each of those friends shares with 3 more every day, so the number of shares triples every day.Day Number of Shares 0 2 1 6 2 18

3. anonymous

1)Write an exponential function to represent the spread of Ben's social media post.

4. anonymous

5. anonymous

@AaronAndyson

6. anonymous

@ganeshie8 @peachpi

7. SolomonZelman

This is a geometric sequence with r=3 and $$a_0$$=2. Or same way with an exponential function, you know the initial value of 2, and the base of the exponential function is 3.

8. SolomonZelman

$$y=a(b)^x$$ a - initial value b - the growth rate

9. Michele_Laino

hint: from your data, we have: $\Large \begin{gathered} N = 2 \times {3^0} = 2 \to day:0 \hfill \\ N = 2 \times {3^1} = 6 \to day:1 \hfill \\ N = 2 \times {3^2} = 18 \to day:2 \hfill \\ \end{gathered}$

10. anonymous

whats the value of x in Y=a(b)

11. anonymous

@SolomonZelman ???

12. SolomonZelman

the x doesn't have a particular value in this case (it is a function, like any other, all you need to do is to fill in for a and b)

13. anonymous

so Y=6 exponent x

14. SolomonZelman

$$y=a(b)^x$$ a - initial value (we said this initial value was .... ?) b - growth rate (this growht rate is... ? -what is the growht rate

15. SolomonZelman

no, don't multiply the 2 and 3

16. anonymous

ok sorry im confused

17. SolomonZelman

when you plugged in for a and b (into the y=a(b)$$^x$$ ) (without multiplying anything, rather, just when you plugged) what did you get?

18. anonymous

y=2(3) exponent x

19. SolomonZelman

yes, y=2(3)$$^x$$

20. SolomonZelman

21. anonymous

lol thank you i thought i had to do more, can you help me with a few more questions

22. SolomonZelman

you can't multiply 2 and 3 together, because 3 is raised to exponent of x, and 2 is not. you get a wrong result, because 2(3)$$^x$$ $$\ne$$ 6$$^x$$ for the following reason 2(3 • 3) $$\square$$ 6 • 6 2(3 • 3 • 3) $$\square$$ 6 • 6 • 6 2(3 • 3 • 3 • 3) $$\square$$ 6 • 6 • 6 • 6 etc....

23. SolomonZelman

yes, I think I can.....

24. SolomonZelman

see how these two expressions are NOT equivalent?

25. anonymous

oooh ok i understand now..

26. SolomonZelman

Good:)

27. SolomonZelman

If you want you can ask in a different post, or use the same post. I don't really care....

28. anonymous

Carter shared his post with 10 friends, who each share with only 2 people each day. Write an exponential function to represent the spread of Carter's social media post.

29. SolomonZelman

Ok, we have the same exact thing, and a same exact function y=a(b)$$^x$$ to fill out, EXCEPT that the numbers are bit different.

30. SolomonZelman

What number of friends who know the post did you start from?

31. anonymous

ok let me try

32. SolomonZelman

33. anonymous

y=10(2) exponent x

34. SolomonZelman

yes, very good

35. SolomonZelman

btw, jst giving you a tip, that you can write an exponent using a caret, the ^ key. (obtained by Shift+6) y=10(2)^x

36. SolomonZelman

^x indicates that x is the exponent. 9so that you don't have to write that x is the exponent every time verbally.

37. anonymous

ok thanks, Graph each function using at least 3 points for each line. All graphs should be placed together on the same coordinate plane, so be sure to label each line.

38. SolomonZelman

oh, so now you have to graph the function from question 1, and the function 2.... right?

39. anonymous

yes

40. SolomonZelman

ok, |dw:1437324320071:dw|

41. SolomonZelman

idk, if this grid will make it easier, and if anything we can use desmos.com

42. SolomonZelman

ok, so your 1st function is y=2(3)^x and your second function is y=10(2)^x

43. SolomonZelman

I will recommend to use x=0 x=1 x=2 for the first and for the second function (use www.desmos.com/calculator because otherwise, you will have a hard time drawing it).

44. SolomonZelman

lets name your 1st function f(x), and second function g(x) (for our convience, for now)

45. SolomonZelman

f(x)=2(3)$$^x$$ g(x)=10(2)$$^x$$ you will need to tell me f(0), f(1), f(2) AND g(0), g(1), g(2)

46. anonymous

im confused, i really didn't understand the graphing at all

47. anonymous

@SolomonZelman

48. SolomonZelman

you just need to label a couple of points (at least 3) on the first function, graph them, and connect them with a curve to get (an approximate) graph of the function. Then, do the same thing for the second function

49. SolomonZelman

I am just advising you to use the points with x-coordinates of 0,1, and 2)