1. C

    Calculus equationthat equals 2 and another that equals 57

    Hi My boyfriend is an engineer and I am looking for two different equations for his birthday card. one should equal 2 and the next should equal 57. thank you !
  2. V

    How to solve these equals?

    Tell me please how to solve these equals? 1.7.5÷1.7.15 1.8.4÷1.8.5 I know only about number theory like C=B÷A. But these equals contain whole numbers. I have no idea how to solve these ones. Please help me.
  3. A

    If Z equals X times Y, then Z-hat equals X-hat plus Y-hat?

    First of all, I don't know if this is "pre-calculus" or not, but am posting the question in this sub-forum because I don't know where else to post it. In my economics textbook, the following note is given: 2 To accomplish this transformation, we apply the rule that, if \, Z\, =\, X\, \times\...
  4. S

    Speed equals distance divided by time

    How do I turn the fraction: Distance Speed =_______ Time into something I can use to calculate the time? I thought it would be: Distance Time =________ Speed
  5. S

    Proving sum of inclusion probabilities equals sample size n

    I am having trouble figuring out where to get started in this proof.Let πi be the inclusion probability of unit i in some sample scheme for drawing n units out of a population of size NHow can I go about showing that the sum of all πi for i from 1 to N is equal to the sample size n?Any help...
  6. A

    Find the determinant D if D equals...

    Hey, hopefully this is the correct place to post! I was looking for help with this textbook problem... Find det D if... Where the back of the book gives the answer as (-1)Nd1d2...dn, N = n(n-1)/2. This problem was actually asked before...
  7. S

    Finding an angle in a triangle where a median from B equals an altitude from A

    Hi everyone, This problem has me stumped as I cannot find an relation to use to solve the problem. The solution had me even more confused. In triangle ABC, altitude AH and median BM intersect inside the triangle and are equal. If <ACB = 41 degrees, find the measure of <MBC. The solution...
  8. J

    Limit of the derivative equals zero implies the limit of the function exists

    I've been tackling a few analysis problems today and have once again hit a bit of a block. I need to either prove or find a counterexample to the following two propostions: \lim_{x \to \infty} f'(x) = 0 \Longrightarrow \lim_{x \to \infty} f(x) exists. \lim_{x \to \infty} f'(x) = 0...
  9. J

    USING YOUR COMPASS ONLY, construct a point on a number line that equals 1/x

    _____0_________________________1______________x 1/x=??
  10. S

    integral from 1 to infiinity of ln x / (x^2) equals 1. How?!!?!?! (PLEASE HELP)!!

    integral from 1 to infiinity of ln x / (x^2) equals 1. How?! (IMPROPER INTEGRATION) I integrated the function to become ln x / (x^2) u = lnx du = 1/x dv = 1/x^2 v = -1/x UV - int VDU lnx * -1/x - - int of 1/x^2 becomes -1/x so - lnx/x - lnx (or close to this) So where the hell does...
  11. A

    I am to graph the function but i cant find where f''(x) equals zero

    f(x)= x^4 - 4x^3 - 8x^2 + 48x f'(x)= 4 (x-2)(x+2)(x-3) f''(x)= 4(3x^2 -6x- 4) my problem is i am unable to get the concavity. what would be my intervals?
  12. L

    Prove that an infimum equals a supremum in different sets

    Suppose that A is contained in the set of all real numbers and is bounded above. Let U be the set of upper bounds, i.e., U={x is an element of the real numbers: x>=a for all a elements of A}. Prove that U is bounded below and that inf U=sup A. (Note: U is not the empty set by the assumption that...
  13. P

    "If equals be added to equals" in Spivak?

    Sorry if this was already posted. I couldn't find any answer anywhere. Also, sorry if this is the wrong forum. In just the 2nd page of Chapter 1 of Spivak's Calculus 3ed edition, Spivak describes to us 3 properties of numbers and then he uses these properties to prove that: a+x=a. Right on the...
  14. I

    on both sides of the equal sides it equals zero, care to take a look? please

    So Im doing math homework and i come across this: 2(8-3q)=-6q+16 I tried to solve it, but it ended up just all equaling zero. Can someone tell me how to solve it?
  15. N

    Does 1 + 1 always equals to 2?

    All, I dont have direct geometry related question but indirect one. My co-worker and I had a debate about 1 + 1 = 2. He says in geometry it is not always the case but I have always believed math is absolute subject and it cant be disputed, and only absolute subject so it was hard for me to...
  16. R

    Prove that absolute value of a equals square root of a squared

    Hello, I am reviewing the precal section of a calculus textbook and one of the problems asks you to prove that Absolute value of a = the square root of a squared I have proved a few other properties of absolute values but for some reason this one is stumping me. Could anyone start me in the...
  17. Z

    Proof, series from k=1 to n of cos(2*pi*k/(2n+1)) equals -1/2

    I have worked out a proof for relationships of complex numbers, and part of my proof requires me to prove this... -1/2 = series from k=1 to n of cos(2*pi*k/(2n+1)) that is, for any positive integer n I've wrote a program that evaluated this for an extended amount of integers n, in every case...
  18. R

    Minimum sum equals sum of minima?

    Hello everyone! If we have functions, f1(t), f2(t), etc. all positive in our observation window, plus: f_1(t) > f_2(t) > ... > f_N(t) for all a<t<b, does it follow that: \int ^b _a f_1(t)dt > \int ^b _a f_2(t)dt > ... > \int ^b _a f_N(t)dt? i.e. is the saying "minimum sum equals sum of...
  19. M

    Find all positive integers n such that euler's phi equals 6

    I haven't the faintest idea how to do this. The homework question reads: Find all positive integer n such that \varphi(n) = 6. Briefly explain why. I know that: if n is prime, then \varphi(n)=n-1. if n=pq, where p and q are distinct primes, then \varphi(n)=(p-1)(q-1). if n=p^e then...
  20. M

    Proof that homomorphism of an inverse equals the inverse of the homomorphism

    g is an element of group G. f(g) is a homomorphism from G to H. Prove that f(g^{-1})=f(g)^{-1}. I'm told the proof is by multiplying the two terms, like this (I guess) f(g^{-1}) f(g)^{-1} = ?? but still cannot see what to do. I also have that e_G, e_H, are the identities in G and H, respectively.