Homework Help

Hello, can someone please help me. So.. I need to build circuit with two reversible motors.. I need to make something like reversible fan system, one fan goes forwards, other backwards.. ofter couple hours they reverses.. I have AC 220V supply. question is.. how can i make this up easier ? The simplest solution is The best. All needed to be automatized my thought is use timing relay, inverters ? What kind of motors i need to use ? reversible AC motors would be The best chose i think.. If i use DC motors that would be messy, needed to change supply from AC to DC, yes, its not so hard, using diode bridge and stuff, but then voltage drops.. and again it's problem…

Ok, let's make it more interesting! Let [math]G[/math] be a group, and suppose there exist three consecutive integers: [math]n-1, n, n+1[/math] such that: [math](ab)^{n-1} = a^{n-1} b^{n-1}, (ab)^n = a^n b^n, (ab)^{n+1} = a^{n+1} b^{n+1}, \forall a,b \in G[/math]. Show that [math]G[/math] is abelian. Also show that such a conclusion needs not hold if the condition is assumed for only two consecutive integers.

The following holds: If from any integer we subtract the sum of its digits, then the result is divisible by 9. E.g. take 1456. The sum of its digits is: 1 + 4 + 5 + 6 = 16. Then: 1456 - 16 = 1440 = 160 x 9. Give a rigorous proof of the above statement! How does it generalize?

i did a ppt about how to do a Vigenère cipher and a caesars shift cipher and i asked someone YA the next method to try and they said RSA. so i was hoping someone could explain how to use the RSA algorithm without the use of a computer? I have been showing the class ciphers that can be used with just a pen and paper. I guess if you have a better idea for the method than i guess that's ok to ps i want to do this one because i have an interest in the subject (it's one of my few interests) and haven't been able to learn any thing new about it because of the mathematics is a little beyond me (i'm about to finish an algebra one class for my high school)

My note i need someone to check the note i made, who know how to 'simplify' and give better idea for better presentation and maybe fix something that wrong in my notes. btw, the most problematic in the notes is Quadractic Function, it's kind of messy and if u got any idea to modify it, post here.. thnx ^^

Punnet square question? True breeding punnet square? I got the right answer but need some clearing up. true-breeding dwarf and true breeding maize plants produced all dwarf plants in F1 . in the f2 generation dwarf and tall plants segregated 3:1 ratio. Dwarf F2 plants self pollinated. what proportion of the resulting plants would be expected dwarf let BB=Dwarf bb=tall BBXbb F1= 1 Bb Bb x Bb F2=1 BB:2 Bb: 1bb now it gets tricky.. so there is a 1/3 chance that BB x BB but a 2/3 chance that Bb x Bb...what I am confused about is what about the chance Bb x BB? ......................................… if BB and BB were crosses all offspring wou…

If the product of two numbers if 5, and the sum of these same two numbers is 4, what's the sum of the reciprocals of these two numbers? I tried: let's say we have two numbers a and b, then a*b = 5 a = 5/b since their product is 4, we get b + 5/b = 4 or b^2 -4b + 5 = 0 but this has no real solutions just imaginary because this function is > 0 for all b I can't factor it and the quadratic formula doesn't work since 4^2 < 4*1*5 also the derivative is 2b -4 = 0 so b = 2 is the minimum since second derivative is positive but that doesn't help either. What do I do?

1) (x-10)[(x+4)(x+1) - 24] - 3[(-11x - 11) + 24] + 8[-21 + 3x] what I get is (x-10)(x^2+5x-20) + 57x-207 The reason that I do not combine them is because I think it is much more difficult to deal with x^3? What should I do here?

If an arrow on Earth is fired into the air and reaches a hight of 125 m and penetrates the ground where it lands to a depth of 25 cm, what is it's deceleration? Of course the acceleration due to gravity is 9.8 m s, but I'm stumped on how to calculate deceleration? I successfully calculated the final velocity to 49.5 m s^-1.

Hey, can you guys answer this question(s) about Stem-cells. What are the ethical arguments for and against stem-cell research? What ethical issues might arise when a drug company funds trials of a new drug it has developed to treat a genetic disorder? Who should determine how the results of transgenic research in plants and animals will be applied?

i was wondering how you find how many electron have been removed if the resultant charge is +3.38 pC (3.38x10-12C). given the charge of an electron being -1.60*10^-19 C

Let P belongs to Mnn be a nonsingular matrix and Let L:Mnn>>>Mnn be given by L(A) = P^-1AP for all A in Mnn. Prove that L is an invertible linear operator. I have no clues how to start this question. What do I need to prove for this question? and why

Let L : V>>>V be an invertible linear operator and let lambda be an eigenvalue of L with associated eigenvector x. a) Show that 1/lambda is an eigenvalue of L^-1 with associated eigenvector x. For this question, the things I know are that L is onto and one to one. Therefore, how to prove this question? b) state the analogous statement for matrices. What does "state" the analogous statement mean? Thanks

hey guys i have recently found my weak point in science. CHEMISTRY i am really bad at chemistry and need this mark like you wouldnt believe. its a grade 10 chemistry assignment. here is the microsoft word assignment less22_u1_reviewassignment.doc if you can asnwer any of those question to help em out it would do wonders for me! thanks! im willing to pay as well....... for the help....my msn is: Norb_y@hotmail.com its a _ mark between norb and y not a space!

I've been given the question of: Derive the following function to find the velocity and acceleration: s=0.3cos(pi/4*t) I am unsure of how to do this properly with this particuar function. It would also help if someone could let me know how to put this function into Graphmatica. I know you have to go to Tools and then down to Functions to enter it into the program, but I don't know how to write it so it will work, as an error keeps coming up when I try to enter it as I have written above. Thanks to all who can help.

hi, i was wondering if anyone knows any websites or videos which effectively cover the lesson on thermal energy, heat and temperature. for some reason i can't seem to pick things up in class so i have to go looking for lessons on my own time. thank you for your help.

Hey, I am currently studying basic chem, and i'm currently writing a paper on precipitation reactions- However I am uncertain as to what exactly an iconic solid is. Is it incorrect to say that it is basically a insoluble ionic compound? If not, then is it of the same structure as a iconic compound? Grateful to anyone who can help

Hi everyone, I'm a sophomore biochemistry, cell, and molecular biology student currently enrolled in a microbiology course. We have been assigned an unknown bacteria and must identify it's taxonomy, genus and species based on a series of tests. My tentative identification of the bacteria currently is Alcaligenes Faecalis. However, a few of the test results are misleading me from my tentative ID, but I'm not sure what else it can be. Below is the list of possible unknowns (some on the list are definitely not possible being they are highly pathogenic). I have also listed my current test results and any relevant attached pictures. (All images taken under the micros…

What property does a membrane pump contain but a membrane carrier does not? I know both flux depend onan electrical gradientbut what are the differences in each? Thanks in advance.

<font face="Arial">1) Let L:R3 >>>R3 be defined by<br> L([1 0 0]) = [1 2 3],<br> L([0 1 0]) = [0 1 1],<br> L([0 0 1]) = [1 1 0]<br><br> How to prove that L is invertible? I have the idea of one-to-one and onto, but I do not know how to apply them to this proof.<br><br> 2) Find a linear transformation L:R2 >>>R3 such that {[1 -1 2], [3 1 -1]} is a basis for range (L). How can I approach this problem?<br><br> 3) Let S = {v1,…,vn} be an ordered basis for vector space V . Let<br> L :V →R^n be given by L(v) = [v]S . Prove that L is an<br> isomorphism( prove that the linear trans…

A friend of mine asked for my help with her homework but it's been so long since last time I solved problems like that I'm not sure if what I did was right. in before you ask me to post what I've done, that won't be possible as I can't take a picture of it right now and don't have the right software to write equations so it would look a mess. Here are the questions: It is estimated that at the current rate of consumption, r gallons per year, the oil supply of the earth will last 200 years. However, the rate of consumption, R(t) is increasing at the rate of 5% per year; that is dR/dt=.05R a) In terms of r, how many gallons of oil are currently available? b) Use …

So this isn't a homework question, but I felt like it was the most appropriate forum. My friend asked: "Ok, so the earth is moving around the sun at 30 km per second. At the same time, the sun is moving around the galaxy at 250 km per second. But when the earth is moving around the sun in the same direction that the sun is moving around the galaxy, the earth is actually moving faster than the sun to get around and pass it. So the earth would speed up to 280km per second. The opposite is also true, in which case the earth going behind and around the sun would slow down to 220 km per second. that is a variance of + or - 60 km per second.....so why the hell don't we feel…

Let L:p2 >>> p3 be the linear transformation defined by L(p(t)) = t^2 p'(t). (a) Find a basis for and the dimension of ker(L). (b) Find a basis for and the dimension of range(L). The hint that I get is to begin by finding an explicit formula for L by determining L(at^2 + bt + c). Does this hint mean let p(t) = at^2 + bt + c? Then, I find that t^2 p'(t) = 2at^3 + bt^2. is the basis for ker(L) {t, 1} and the basis for range(L) {t^3, t^2}? Thanks

My first question is... In JFLAP there is a square symbol when building a turing machine. What does that symbol stand for? Does it stand for empty string? My second question is... for a turing machine that reads for example ####abbcb#### and when read all symbols give ####bbcb#### then the turing machine doesn't need to read all symbols, right? Only to the last b? Or does it need to read all symbols to be 'valid' for that input string? Last but not least I would appreciate if someone could take a look at the following turing machines and automata's and let me know if I understood it correcly and if something is wrong please let me know. Indata ####abbcb#### O…

Hi all, first post On my calculus exam we had the following question: find the arc length of [latex] \frac{e^x+e^{-x}}{2}[/latex] from zero to a I subbed in hyperbolic cosine and found the arc length to be sinh(a) Any thoughts? Thanks. I only ask because the arc length was crucial to later questions involving area of rotation and none of my classmates used the hyperbolic cosine substitution My solution (don't laugh): [math](\frac{dy}{dx})^2=sinh^2(x)[/math] [math]L = \int_{0}^{a} \sqrt{1+sinh^2(x)}dx[/math] [math]L = \int_{0}^{a} \sqrt{cosh^2(x)}dx[/math] [math]L = \int_{0}^{a} cosh(x)dx[/math] [math]L = sinh(a) - sinh(0) = sinh…