<p>yeah i got 2250 too…no idea how ppl are getting 2500…i thought that was a freebie lol…■■■.</p>
<p>btw 6b) F(-4)= 8-2pi. idk y some1 here was adding five.them telling u f(0)=5 is completely obsolete.</p>
<p>what did the integral from 25 to 30 mean for the cable company problem?</p>
<p>no, it’s definitely $2500 because of two ways:
what dstfan wrote
or
integration of 120 - 6squareroot of x, with limits 0 and 25.</p>
<p>jpl: I wrote that it was a loss of profit since by selling 30 m you are gaining less money than you would sell a 25 m.</p>
<p>f(-4) is not 8-2pi
Its 5-(8-2pi) i think</p>
<p>ih8calc: Lol. I did it the wrong way. $120(25) - [6<em>sqrt(25) * 25] = $2250 for me.
But it’s suppose to be $120(25) - integral from 0 to 25 of 6</em>sqrt(x) = $2500</p>
<p>It was 2500. You cannot sub in 25 for x in that equation, you need to subtract from 120<em>25 the definite integral of 6</em>sqrt(x) from 0 to 25, which is 500.</p>
<p>dstfan u dont include the 5 it was a trick. no matter wat they can say area under the curve is integral. if u think about it the f(0)=5 is just a value on the graph of f. U dont have to compensate on the area for that. JERRY JUST DO THAT INTEGRAL PLEASE OMG. IT DOES NOT = 2500 IF U DO IT RIGHT. INTEGRATE 120-6radx U GET 120x-4x^(3/2). FOR THE LOVE OF GOD JUST PLUG IN THE LIMITS.</p>
<p>Wow, I just figured out how to do #6. I completely blanked out on that one on the test itself…and NOW I see its fairly easy. Sheesh, I hate it when this happens.</p>
<p>so we are clear wat is the definite integral of 6radx please</p>
<p>ih8calc, its was not a trick, thats how you are supposed to figure out the value of f(-4).</p>
<p>btw im wrong on 500 my bad i kept doin 25^(3/2) wrong. apologies. dstfan if it asks for f(-4) and they show u a graph u just have to do area under the curve. idky u would even add 5.</p>
<p>If you start out a f(-4) and add the area under the curve until x=0 you get f(0).
Do the opposite for finding f(-4)</p>
<p>ih8calc: are you saying that I am wrong about the integration equation? It is right. Since you have already integrated the function, why don’t you just plug in 25.</p>
<p>Why add 5? Because f(0)=5.</p>
<p>if ur sayin the area under the curve =f(0) then ur sayin that the area under the curve =5 which is wrong… we went over this question in class its def 8-2pi…</p>
<p>u see a semicircle radius of 2 do the area of a full circle and the square around it… u get 16-4pi now divide by 2. 8-2pi.</p>
<p>user 007: it some sort of rule. I have to learn that from doing previous years released questions.</p>
<p>For problem 6b.</p>
<p>4<br>
S f ’ (x) dx = f(4) - f(0). Thus,
0</p>
<p>4
S f '(x) dx + f(0) = f(4).
0 </p>
<p>The area under the curve from zero to four represents the value of the integral. Add this amount to the value of f(0) and you’ll have the right answer.</p>
<p>-4<br>
S f ’ (x) dx =
0</p>
<p>0
-S f '(x) dx = -[f(0) - f(-4)]. Thus,
-4</p>
<p>0
-S f '(x) dx + f(0) = f(-4).
-4</p>
<p>The area under the curve from negative four to zero represents the value of the integral. Subtract this amount from the value of f(0) and you’ll have the right answer.</p>
<p>lol, it was definitely 2500. Whoever said otherwise doesn’t know how to integrate on their calculator.</p>
<p>I got 2500, too. I liked the profit problem; it was fun to do. :)</p>