<p>quick question… for the f(x+3) one, why couldn’t the function have been logx?</p>
<p>was logx even an answer or was it for sure Lnx?</p>
<p>are you that desperate?..</p>
<p>I used the initial value for a, naturally: 400</p>
<p>and for b, I found it by finding x in (400x^5=850), so x is 1.1627=b</p>
<p>Anyway, the question was something to the effect of the sale of cell phones… Initially, 400 are sold. In 5 weeks, 850 are sold… Using exponential regression, how many weeks wouild it take to reach 10,000.</p>
<p>like I said, I put 400x^5=850 to find the rate, or whatever you call it…</p>
<p>then I substituted that for b into the equation 10000=400(1.1627)^x and found x=21.3531</p>
<p>Happy? lol</p>
<p>^thats exactly what i did… why are people saying its 24?</p>
<p>What was the f(x+3) question, miamiboy? I’m positive i got it right…i can help you out…Give me the question so i can get the overall gist of it.</p>
<p>Idk, but hopefully we did well… Have you noticed any others that you got wrong and didn’t even think you would? because, for the most part, I thought I did well, except for the fact that I couldn’t finish the last four…</p>
<p>it was like f(x+3) = f(x) x f(3) and it said for which of the functions that was true for</p>
<p>for which of the following functions does f(x+3) = f(x) * f(3)</p>
<p>log(x), e^x, etc.</p>
<p>log(x+3)… log(x) * log(3), which does not equal log(x+3) — FALSE</p>
<p>e^(x+3)… e^x * e^3 = e(x+3) — TRUE</p>
<p>something along those lines</p>
<p>^borderline… depends on the curve–I took the SAT’s</p>
<p>But in the Blue book, a raw score of 45 (3 skipped and 2 wrong) would be a definite 800, no? Even 4 skipped and 2 wrong is an 800 on both the blue book tests, no?
I think the cutoff for the curve is usually around a 43, at the least, raw score for an 800. Correct me if im wrong</p>
<p>3 skipped and 2 wrong gives u a raw score of 44.</p>
<p>and in the blue book, 44/50 is the minimum for an 800.</p>
<p>Oh right right…but i don’t understand, there wasn’t any log(x) option from the 5 choices they gave you…and plus i plugged in numbers. If you plug in a number, you will get the correct answer. If you want me to give you an algebraic response, you have to be clearer…it seems like you agree with the correct answer.</p>
<p>3 skipped and 2 wrong yields 45 (45-(.25 x 2)= 45-.5=44.5 so approx 45 rounded.</p>
<p>r u talking about the f(x+3) question? there was a log(x) option. and what exactly do you mean “you plugged in numbers”?</p>
<p>^oh thats right, my bad</p>
<p>Ok, look…If you plug in a number, lets say 2 is x, into the functions they give you, then whichever function that held that value to be true is correct. So For example : f(5)=f(2) x f(3)…then you would go to the mc they give and then plug 2 in for x. Its hard for me to explain cuz i don’t know the EXACT QUESTION WITH THE EXACT MC’s.</p>
<p>Can someone explain why the exponential regression is NOT 21?</p>
<p>It is 21…I realize now why…the question was this or something like this:
A company initially sold 400 cell phones and in the 5th week it sold 850 cellphones. Then in the 10th week, it sold 1520 (or something like that) cell phones. Then how many weeks would it take to sell 10,00 phones, using an exponential regression model? </p>
<p>So according to me this is the explanation…algebraically.
y=ab^x (exp. regr. equation)</p>
<p>a=400
x=5 because we have to solve for b
y=850
so…850=400b^5
Then its…850/400=b^5…log(2.125)=log(b^5)…0.327=5log(b)
.327/5=log(b)
0.06547…log(b)…10^0.06547=1.1627=b.
10,000=400(1.1627)^x…Im not solving for x its too long (and i have a life) but you use the log properties and clean it up…you should get 21 rounded.</p>
<p>I have a quick q…the question about the geometric sequence with common ratio of -3…at what point in the test did that question appear?</p>
<p>For which of the following functions is this statement true? f(x+3) = f(x) * f(3).</p>
<p>A) f(x) = x^2
B) f(x) = 4x+7
C) f(x) = log(x)
D) f(x) = |x|
E) f(x) = e^x</p>
<p>those were not the actual options, but i’m giving you an example. now explain to me how any of those but option E can work.</p>
<p>"</p>
<p>It is 21…I realize now why…the question was this or something like this:
A company initially sold 400 cell phones and in the 5th week it sold 850 cellphones. Then in the 10th week, it sold 1520 (or something like that) cell phones. Then how many weeks would it take to sell 10,00 phones, using an exponential regression model?</p>
<p>So according to me this is the explanation…algebraically.
y=ab^x (exp. regr. equation)</p>
<p>a=400
x=5 because we have to solve for b
y=850
so…850=400b^5
Then its…850/400=b^5…log(2.125)=log(b^5)…0.327=5log(b)
.327/5=log(b)
0.06547…log(b)…10^0.06547=1.1627=b.
10,000=400(1.1627)^x…Im not solving for x its too long (and i have a life) but you use the log properties and clean it up…you should get 21 rounded. "</p>
<p>OH ****. i just realized. if you use that method, but use 1520=400b^10, you get b as 1.1428, which would make the answer 24. if you use 850=400b^5, you get b as 1.1627, which makes the answer 21. can we get a mathematical genius to help? please?</p>
<p>Choklitrain - it was pretty early. I’d guess in the early 20s</p>