Recent content by kawsar

Hmmm... The first two formulae have 3 different variables and the Lambda. Will the basic Simultaneous Equation solving method work with that?

Thanks! When you say combine do you mean write one equals the other and then try and simplify it? Could you do your step one please.

Sorry guys... A few more pointers please! Don't know what's wrong with me but can't seem to solve the eqns for some reason...

Ok. You mean the constraint itself and not the partial derivative in respect to Lambda. I'll see if that gets me anywhere. Thanks!

1. Use the method of Lagrange multipliers to nd the minimum value of the function: f(x,y,z) = xy + 2xz + 2yz subject to the constraint xyz = 32. I understand the method how Lagranges Multipliers is donw done but seem to have got stuck solving the Simultaneous Equations involving the...

I get -1 Correct?

2e^(2x) so the other one is y*e^(xy) and x*e^(xy)... Am I correct?

Hmmm... As I suspected! Could you tell me the partial derivatives of e^xy please? Thanks.

1. Find the directional derivative of the function f(x,y) = e^{xy} at the point (-2,0) in the direction of the unit vector that makes an angle of \pi/3 with the positive x-axis The vector to make into a unit vector is (\sqrt{3},1) and e^{xy} differentiated with respect to x and y is both...

I thought it was the standard that Universities don't allow Calculators at all... Makes you think more (which is better) but some questions become a tad longer which doesn't help when you're running out of time...!

Here is what it says on the past exam paper it came from: Calculators are NOT permitted in this examination. So, no calculators of any kind allowed by the looks of it. I might have to email one of the lecturers to see what they say about this. Seems a tough one having to work out the modulus...

Yep, that's what I get as well, but how would I plot that root on an Argand Diagram? I could work out the a and b (to make it into the format a+bi) using a calculator but I'm not allowed to use one you see. Any ways I could do that without the use of a calculator etc.? Thanks!

1. Find the cube roots of the complex number 8+8i and plot them on an Argand diagram Thats the problem, I've had a go at the solution and came up with 3 solutions using the \sqrt[n]{r}*(cos(\frac{\theta+2\pi*k}{n})+isin(\frac{\theta+2\pi*k}{n})), but the answers (roots) I get, I can't plot it...