1. A

    Advanced Matrices and Cryptography Question Help

    Hello, I was stuck on the following question. 'Your task it to crack the following code and find the encrypted word. To make your task easier, the following information about the encoding matrix is given: Position 1,1 in the encoding matrix is an even number. The decoding matrix only contains...
  2. C

    Internal Rate of Return, Simplifying Equation Help

    Hi, I have an Internal Rate of Return question I need help with please. I have been given the answer for r, which is 0.208, however I cannot understand how the following equation: -300 + -300/(1+r) + 800/(1+r)^2 = 0 when multiplied by (1+r)^2, becomes: 300r^2 + 900r - 200 = 0 Could someone...
  3. A

    Show that A is closed under multiplication

    (The star indicated multiplication) "Let A = {r*k +1 | k∈Z^+}, Where r is ANY fixed positive integer. Show that A is closed under multiplication." In words: Let A equal the set of r times k plus one, where k is an element of all positive integers. I am very familiar with equations that are...
  4. F

    Matrix multiplication true / false

    A and B are matrices. If A is invertible and AB = 0, then B = 0. Can you prove this is true or use any example to show that it's false? I don't understand how to find a non-zero matrix B that when multiplied by A gives us 0. I know the equation Ax = 0, but I don't know how to apply it to find...
  5. M

    Independence and Multiplication rule help

    Hi guys, I'm back again with another question hopefully you guys can help me. [Question] We have a fuse box with 20 fuses, 5 of which are defective. If 2 fuses are selected at random, in succession, and without replacement, what is the probability that both fuses are defective? [SOLN] A =...
  6. W

    5 th grade math - decimal multiplication using models

    Hi, This might seem a silly question to you all Math experts. I am having problem understanding the logic here. I understood the process of multiplying decimals using grid. Here's the question: The distance from Charlene's house to her school is 0.8 miles. Charlene rides her bike 7 tenth of...
  7. Jason76

    Closure Under Scalar Multiplication

    When discussing proving whether something is a vector space or sub-space, then this comes up: How to prove closure under scalar multiplication. May I see a simple example, to get a basic idea?
  8. G

    Multiplication of scientific notation problem

    Hi there how would i solve this equation 5.5 Mol x (6.02x10^23 Atoms) / 1 MOL
  9. N

    Multiplication and Subtraction of logs with different bases.

    \text{If }a=\log_{12} 18, b=\log_{24}54\text{, then find the value of }ab+5(a-b) I am trying in different ways to equalize the bases. But I can't do anything as the bases are unequal.
  10. A

    Different Roots Multiplication

    Usually I double the square/cube and halve the root, or double the root and halve the square/cube until they're similar, but I don't know what to do with this one. That's probably the wrong way of going about it, anywho... Answer being 18.
  11. N

    please help with abridged multiplication

    multiply by the formula or vice versa - to determine the polynomial multiplied. 1. (10-3y)2 = 2. (m+3) (m+3) = 3. (5x4y2)2 = 4. (m+n)2 = 5. (s-t)2 = 6. (2a+5)2 = 7. (-a+3c)2 = 8. (-5x-3y)2 = 9. c2 - 2cd + d2 = 10. (10a+2)2 = 11. (3m2 +4n) (3m + 4n) = 12. (5-x) (5-x) = 13. (x-y)2 =...
  12. M

    Compute binary multiplication without multiplying

    Hi all. As the tittle says, the problem is to find a way to compute the result of the multiplication of 2 binary variables without multiplying them. I have 2 binary variables X and Y, such that the summation tables is: X Y X+Y 0 0 0 0 1 1 1 0 1 1 1 2 The subtraction table is: X Y X-Y 0 0 0...
  13. T

    matrix multiplication

    \begin{pmatrix} 2&1\\-4&0\\-3&2\end{pmatrix} \begin{pmatrix} 2 \\ 3 \end{pmatrix} = \begin{pmatrix} 7\\-8\\0 \end{pmatrix} is this correct ?
  14. topsquark

    S3 multiplication table

    1) Do generators exist for S3 (the symmetric group)? I thought the symmetric groups all had generators? 2) When working out products of elements in S3 I get that (231)(213) = (123). This is a product of two 3-cycles and they are not inverses so (123) has to represent a 3-cycle. How do I...
  15. L

    Question concerning roots and multiplication

    if I have 2*sqrt(x) *x, what is the simplifed version of this? The reason I ask is that I am working on a question Online Derivative Calculator ? now with steps! (if you click this link and if it doesn't show the working, just click go) and I can get the answer it says, but not the...
  16. D

    Multiplication shift cipher with k-graphs

    Ok, I've been looking at a worked example of a question I can't understand what's going on a certain point. There is a multiplier of 17, a shift 41 and k=2. PA needs to be enciphered. P has the value of 16 and A has the value of 1. PA is converted to a pair with the sum: 16 x 62 + 1 = 993...
  17. O

    Help wanted with basic math multiplication!

    Hello! Can you please help me with how to solve this calculation?
  18. R

    Matrix groups and conjugate

    Please see attached file. I understand that for part a K is a normal subgroup of L through strategies eventually equating with a lower traingular matrix such like L. But when i try to manipulate H i end up with a really weird final result?! such as fractions and a lengthy multiplication in the...
  19. J

    Hi, having problems with a complex number multiplication

    Hi everyone, I'm Joanne and currently studying to become a maths teacher (1 year in to studying). I'm having problems trying to work out the below multiplication. I've worked out that the polar form of (2-2i)^12 is ( sorry about the ?'s) But I am unsure of what to do next. Do I work...
  20. J

    Multiplication of supremum

    Sup(A*B)=supA*supB A,B >= 0 how can solve this topic?