# variables

1. ### can anyone knows the formula for these variables ?

I had these variables in my calculations and I can't find there formula ! thanks
2. ### Using variables in matrices TI-82

Hello everyone, Does anyone know how to put in variables in matrices using calculator Texas TI-82. I am trying to solve Ax=b for some unknown X variables. When I put the unknown variables as X1,X2 etc. they will immediately become zero. Regards
3. ### How to Drive Tariff from two VARIABLES?

Hello Everyone, I need your assistance here with the following problem and I'm sure someone will help me. :) I've trucking rates which are based on fixed kilos - the range starts from 50 kilos to 5000 kilos. Condition is whatever the volume of the cargo is we have to multiply it by 200 and...
4. ### Equation with 3 variables

Solve for x,y,z -integers , 3^{x}+4^{y} =5^{z}.
5. ### Standard deviation on scaling of random variables

I have the answer already (based on simulations), but want to know exactly which theorem/ law is at play: Suppose X1, X2, X3, X4 are 4 positive random variables such that X1+X2+X3+X4=1. Suppose I scale them with known constants C1, C2, C3, C4, respectively, then look at the function below...
6. ### Central Limit Theorem for weighted summation of random variables?

Here is a quick question:- If X1, X2, X3,.... X20 are 20 random variables (independent/ idd) What would be the result of: 2*X1+5*X2+1*X3+18*X4...+0.5*X20? (linear combination of the random variables, with fixed known constants). Will the above function form a normal distribution if we...
7. ### Convergence of mean of inf series of random variables with different distributions

Please see the attachment figure. I have an arithmetic mean of an infinite series of independent random variables. However, these variables can come from 5 different independent normal distributions, and each of the 5 distributions are equally probable (each having its own mean and standard...
8. ### Linear combination of random variables, convergence for a large number of variables

Hi, I have positive random variables X1, X2, X3, ..., Xn such that their sum=1 (so they are random, subject to constraints that each Xi is positive their sum has to be 1.. so all are fractions). Now, I have a function f=C1.X1+C2.X2+C3.X3.....+Cn.Xn where C1, C2, ....Cn are known...
9. ### Independent discrete random variables probability

Independent random variables X, Y, Z take only integer values: X - from 0 to 7, Y - from 0 to 10, Z - from 0 to 13. Find the probability P (X + Y + Z = 4) if it is known that the possible values of X, Y, and Z are equiprobable. The solution is attached below; however, I don't understand where...
10. ### Intersection of three lines - aka a system of three equations with three variables

So I'm supposed to find the value of m for which these three lines intersect at the same point: mx+2y-1=0 2x+my+3=0 x-y-3=0 One of the many things I tried was to write all three in slope-intercept form like this: y=(1-mx)/2 y=(-3-2x)/m y=x-3 Then I thought, I can just equate the second and...
11. ### Function of two variables and differentiability

I read the following three statements for a real valued two variable function 'f' which are true: 1. I know that when the function(of two variables) is differentiable, then it implies that the function is continuous and partial derivatives of the function exists. 2. I also know that if one of...
12. ### Inequality proof with two variables

Prove inequality without calculus. Given two natural numbers x,y and x^y > y^x \; \;, show that x<y.
13. ### Using substitution of variables to find area

Find the area in the first quadrant limite by the curves xy=5, xy=10, y=ex and y=(e^9)x The answer should be an exact rational number. ps: You are expected to substitute variables
14. ### Solve an equation with two variables

Hello, I am trying to solve this equation, but I can't find any way to do that. The solution has to be a=b=0, but how can I prove that? Thank you in advance. 2e^(a^2)+ln(b^2+1)=2
15. ### functions of several variables

How do I find the range for g(x,y) = sqrt(y-x) - ln (9 - x^2 - y^2)? Thanks.
16. ### functions of several variables

How do I find the range for ln(9 - x^2 - y^2 - z^2)? Thanks.
17. ### Solving a 3 variables equation, one happens to cause an oddity

Hey, so we had this question in class: Given that the relationship between distance (m) and velocity (v) of an object is v^2 = 1 - m^3 Find the acceleration of the object when m=1 By taking the derivative of each side with respect to t 2v \frac{dv}{dt} =...
18. ### # of linear equations <> # of variables

How to solve the following equation: (I) is imaginary unit A+I*B= [(C*X1+D*Y1+ E*X2+F*Y2)]+ I*[ (G*X1+H*Y1+ M*X2+J*Y2)] ---- This equation should satisfy several boundary conditions. at each point of these boundary the constant [A, B, C,D,E,F,G,H,M,J] are known. Number of points of...
19. ### linear equation with complex variables

G'day all, How to solve the following equation please, (A, B, C,.. real constants, while X, Y are complex variables: knowing that the equations are determinate (applied for several inputs of data so that the number of variables=number of equations A+iB= Real [(C.Real(x)+D.Real(y)+...
20. ### Inverse of function with 3 variables

So, I do have a formula that generates a point, to do so, it will compute with 3 variables (u, v, a) and I want to find out what the variables are for a given point. Here's the function: \binom{u}{v}+\frac{u*\sin(e)-v*\cos(e)}{sin(a)}*\binom{\cos(a+e)}{\sin(a+e)} +...