Recent content by brendan

Sorry guys, I should have said how many wells would have to be drilled to strike oil 3 times in in succession. I should be using the Negative binomial for that calculation. It is the number of successes k divided by the probabilty of success p so k/p = 3/0.2 = 15 wells drilled before...

So, Let say I have 5 tries there are 5P3 = 20 ways of getting 3 in a row. and there are 5! = 120 combinations. so would that make the probability 5P3 divide 5! = 1/6 ? regards Brendan

Is the Expected value of striking oil 3 successive times just 0.2 * 0.2 * 0.2 = 0.008 ? regards Brendan

g(x,y) = x2+y2=25 Now we have y = -1/2 so x = sqrt(25-y2) or -sqrt(25-y2) = sqrt(99/4) or -sqrt(99/4) So we have two solutions f(x,y)= x2-y = fsqrt(25-y2) ,-1/2) = 101/4= 25.25 (maximum) f(x,y)= x2-y = f(-sqrt(25-y2) ,-1/2) = -97/4= -24.25 (Minimum) Is that better?

g(x,y) = x2+y2=25 Now we have y = -1/2 so x = sqrt(y2+25) or -sqrt(y2+25) = sqrt(101)/2 or -sqrt(101) So we have two solutions f(x,y)= x2-y = f(sqrt(101)/2,-1/2) = 103/4 = 25.75 f(x,y)= x2-y = f(-sqrt(101)/2,-1/2) = 103/4 = 25.75 So they are both the maximum

Homework Statement Use Lagrange Multipliers to find the Maximum and Minimum values of f(x,y) = x2-y. Subject to the restraint g(x,y) = x2+y2=25 Homework Equations gradient f(x,y)= gradient g(x,y) The Attempt at a Solution I have found the gradients of f and g to be f(x,y) =...

Homework Statement Assume the F(x,y,z) = 0 defines z implicitly as a function of x anf y. Show that Homework Equations ∂z/∂x = -(∂F/∂x)/(∂F/∂z) The Attempt at a Solution I know this question is asking about the Implicit function theorem So I start with F(x,y,z) =0 define...

Sorry, the unit vector would be < 1/6 , -1/2 , 2/3 > / < sqrt(26)/6 , sqrt(26)/6 , sqrt(26)/6 > regards Brendan

So If I use the gradient <1/6 ,-1/2 ,2/3> and find its unit vector which is <sqrt(26)/936, -sqrt(26)/312, sqrt(26)/234 > than find the dot product of them both <1/6 ,-1/2 ,2/3> . <sqrt(26)/936, -sqrt(26)/312, sqrt(26)/234 > which is sqrt(26)/6 the magnitude of the...

Homework Statement Find a unit vector in the direction in which f(x,y,z) = (x-3y+4z)1/2 increases most rapidly at P(0,-3,0), and find the rate of increase of f in that direction Homework Equations The Attempt at a Solution I've calculated the unit vector to be <0,-1,0> and...

So, It would be 4Choose2 * Px=0.2 = 4!/((2!)(2!)) * (1/5)2* (4/5)2 *(1/5) = 0.03072 regards Brendan

Hi Guys, I have been given the probability that a drill strikes oil in a region = 0.2. I know that if I wanted to find the probabilty of say striking oil 3 times out of 5 wells It would be 5Choose3 = 5!/((2!)(3!)) * (1/5)3* (4/5)2 = 0.0512 My question is how would I go about...

Sorry Guys, My mistake The functions for Cauchy-Riemann Equations are: u(x,y)= excos(y) v(x,y) = exsin(y) Your were right they were in a previous question.

I have to take the partial derivatives of the functions u(x,y) and v(x,y). I have been told that x = r cos(Θ) y= r sin(Θ) So I suppose I have to find the partial derivatives of: u(x,y) and v(x,y). And they should equal each other if they are Cauchy-Riemann Equations. ∂u/∂x = ∂v/∂y...

Homework Statement Show that u(x,y) and v(x,y) satisfy the Cauchy-Riemann Equations. x = r cos(Θ) y= r sin(Θ) Homework Equations Cauch-Riemann sum ∂u/∂x = ∂v/∂y The Attempt at a Solution My questions are: 1. Do I convert the x and y values to rectangular...