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09272009, 04:47 PM  #1  
 
Class 3R Laser Join Date: Feb 2008 Location: Norfolk, Uk
Posts: 2,364
Rep Power: 148 
Hey guys, I've had a really tough day today, and am now struggling with the easiest of maths problems. I can see this happening a lot, so I have had the idea of giving a prize at Xmas to the person that I have judged to have helped me the most. Here are the problems for today: 1. express 1  (root a)^4/3 in the form a^n 2. by letting y=x^1/3 find the values of X for which x^1/3  2x^1/3 = 1 3. express in the form 2^n a. 2^1/3 + 2^1/3 + 2^1/3 + 2^1/3 b. 2^100  2^99 c. 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 4. solve the equation 125^3x = 25^x2   5^x+4 3125 5. find the equation of the straight line that passes through the points (3,1) and (2,2). Find point of intersecton of x axis Thanks guys
__________________ Bender is back! Last edited by robjdixon; 09272009 at 05:55 PM.  
09272009, 05:52 PM  #2  
 
Class 3B Laser Join Date: Nov 2008 Location: Germany
Posts: 4,239
Rep Power: 292 
1. (root a)^4/3 ===> a^2/3 2. x^1/3  2x^1/3 = 1 ====> x=8 or x=1 3. a. 2^1/3 + 2^1/3 + 2^1/3 + 2^1/3 ===> 2^2/3 b. 2^100  2^99 ====> 2^99 c. 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 ==>2^33/10 4. 125^3x = 25^x2 ==> I guess x=4/7 and what does 5^x+4 3125 mean? 5. y=3x/5 + 4/5 If you specify what problem 4 stands for I can help ya with it too. Last edited by Elektrotechniker; 09272009 at 05:54 PM.  
09272009, 05:57 PM  #3  
 
Class 3R Laser Join Date: Feb 2008 Location: Norfolk, Uk
Posts: 2,364
Rep Power: 148 
Thanks bud. Is it too much to ask for you to show a little working. I edited the post to show 4 more clear. I need to find x. Also, the prize is a 70100mW red laser that runs on 1AA battery  pretty unique if I may say so myself Rob
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09272009, 06:00 PM  #4  
 
Class 3B Laser Join Date: Nov 2008 Location: Germany
Posts: 4,239
Rep Power: 292  Ok.. So 125^3x = 25^x2 ==> x=4/7
 
09272009, 06:04 PM  #5  
 
Class 3R Laser Join Date: Feb 2008 Location: Norfolk, Uk
Posts: 2,364
Rep Power: 148 
Thanks. How would I got about working through the rest? If you can do those, you get 10 points (5 for answers and 5 for working). I'll keep a tally, and send the laser out for xmas
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09272009, 06:15 PM  #6  
 
Class 3B Laser Join Date: Nov 2008 Location: Germany
Posts: 4,239
Rep Power: 292 
1. (root a)^4/3 = a^1/2*4/3 = a^2/3 2. x^1/3 2x^1/3 = 1 ==> y 2y^1 = 1 ==> y 2/y = 1 ==> y^2 2 = y ==> (y2)(y+1)=0 ==> y=2 or y=1 y=x^1/3 ==> 2=x^1/3 ==> 2^3=x ==> x=8 y=x^1/3 ==> 1=x^1/3 ==> (1)^3=x ==> x= 1 3. a. 2^1/3 + 2^1/3 + 2^1/3 + 2^1/3 = 4*2^1/3 = (2^2)*(2^1/3) = 2^(2+1/3)=2^7/3 (sorry i wrote it false in last post ) b. 2^100 2^99= (2^99)*2  2^99 = 2^99*(21)=2^99 c. 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 + 8^0.1 = 8*8^0.1= (2^3)*2^0.3=2^3+0.3=2^3.3=2^33/10 4. 125^3x = 25^x2 ==> 5^3*3x=5^2(x2) ==> 5^9x=5^2x4 ==> 9x=2x4 ==> x=4/7 5. λ= (2(1))/23= 3/5 so y(1)=(3/5)*(x3) ==> y=3x/5 + 4/5 I had a hard time writing these in this post but finished them on paper in about 5 min. If you want anything else just shoot it. Last edited by Elektrotechniker; 09272009 at 06:18 PM.  
09272009, 06:18 PM  #7  
 
Class 3B Laser  Quote:
__________________ The difference between an ignorant and a wise is that the wise knows the limits of his knowledge while the ignorant ignores the limits of his ignorance. Learn how to use Opera and tell me about your experience here! Wicked Lasers Evolution Pro 130mW > Review Rayfoss 150mW waterproof Rayfoss 200mW focusable torch > Review Dealextreme 5mW true laser pointer Dealextreme 50mW true laser pointer Dealextreme 100mW true laser pointer Laserlands 30mW disco laser > Review 5mW pointers (many of them) DX 200mW Red laser (Dilda) > Review 120mW PHR custom build 200mW GGW custom build Focalprice 7$ green&bluray laser goggles Dealextreme tripod and clamp for laser holding > Review DIY 3 motor Spirograph > Review HLPM2 laser power meter  
09272009, 06:20 PM  #8  
 
Class 3B Laser Join Date: Nov 2008 Location: Germany
Posts: 4,239
Rep Power: 292   
09272009, 06:31 PM  #9  
 
Cereal Eater 
I'm working on them, gimme some minutes and I'll give you definitive answers Okay, took two shots of the paper with my D90, of course improved with PS CS4 for visibility (I know they look like crap, we're going for clarity with numbers and the pencil I used is crappy). Silvershot, you missed both denominators on ex. 4. so the previous answer is not correct (though it is correct for the equation without the denom. ). All answers down there, also, the graph is just to complement, do it with a ruler and it'll look much better. (BIG ass resolution) 1: 2: Last edited by nikokapo; 09272009 at 07:18 PM.  
09272009, 07:25 PM  #10  
 
Class 3B Laser Join Date: Nov 2008 Location: Germany
Posts: 4,239
Rep Power: 292 
I didn't know  meant denominator.
Last edited by Elektrotechniker; 09272009 at 07:27 PM.  
09272009, 07:29 PM  #11  
 
Cereal Eater  Quote:
2+2 = 4 anywhere. The confusing part was that 5^x + 4...I had to to the procedure all over again for that. It's not a competition, I'm not saying the mistake was your fault. However you did miss the linear function's root on ex. 5. I gave him the procedures since getting just the final answer won't teach him how to do the excercise. Nevertheless, rob, next time you should ask for help with solving them, not just asking for full answers. Math is learnt the hard way EDIT: Oops, seems you've edited your post, do you want me to edit mine or leave your last answer unquoted?  
09272009, 07:45 PM  #12  
 
Class 3R Laser Join Date: Feb 2008 Location: Norfolk, Uk
Posts: 2,364
Rep Power: 148 
Sorry about 4 silver shot  I was in a manic rush. For this one, I shall give 10 points each, as you both gave different ways of answering that were both very helpful. Edit: @ niko, when I asked for help, I meant the solutions, not the answers  my maths teacher is sneaky, and doesn't collect in the homework, but sets a test with similar questions at the start of the lesson, so people that copied the answers are found out.
__________________ Bender is back! Last edited by robjdixon; 09272009 at 07:47 PM.  
09272009, 08:10 PM  #13  
 
Class 3B Laser Join Date: Nov 2008 Location: Germany
Posts: 4,239
Rep Power: 292  Quote:
I don't mind about the edited post. As for the ex. 5. He asked the equation of the straight line didn't he? so I find λ( factor management, slope) and considering the line passes from each of the points, no matter which one you use, it's the easiest way to find the equation( imo ), plus I wrote him how to do it, the solution. @ rob, why don't you do these exercises on your own, so you practise your maths? Last edited by Elektrotechniker; 09272009 at 08:18 PM.  
09282009, 07:52 PM  #14  
 
Class 3R Laser 
Wow, you leave homeworks nearly as late as me! :P If I saw them scanned in, I might be able to help more quickly (I hate having to interpret "computer maths". Is this all Y11 GCSE work or is it beyond the curriculum? My school do the curriculum in an odd order however, so I'd guess our work doesn't line up accurately.  
09282009, 07:57 PM  #15  
 
Class 3R Laser Join Date: Feb 2008 Location: Norfolk, Uk
Posts: 2,364
Rep Power: 148 
This is A level maths. I'm doing the whole A level this year though, so going 2 times as fast as everyone else. The reason I left it this late was that I thought my genius brother was coming home from uni for a few days, and he might be able to help me Quote:
Next time (if there is a next time) I'll scan it. And if there isn't a next time, I'll just draw niko and silvershot randomly, and give one the red, and the other something else Rob
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11022009, 10:03 PM  #16  
 
Class 3B Laser 
Do you guys know of the existence of the WIRIS? It would save you tons of work there!
__________________ The difference between an ignorant and a wise is that the wise knows the limits of his knowledge while the ignorant ignores the limits of his ignorance. Learn how to use Opera and tell me about your experience here! Wicked Lasers Evolution Pro 130mW > Review Rayfoss 150mW waterproof Rayfoss 200mW focusable torch > Review Dealextreme 5mW true laser pointer Dealextreme 50mW true laser pointer Dealextreme 100mW true laser pointer Laserlands 30mW disco laser > Review 5mW pointers (many of them) DX 200mW Red laser (Dilda) > Review 120mW PHR custom build 200mW GGW custom build Focalprice 7$ green&bluray laser goggles Dealextreme tripod and clamp for laser holding > Review DIY 3 motor Spirograph > Review HLPM2 laser power meter  
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