Recent content by davidp92

Hi all So I'm having a really hard time choosing to pursue a specific field of science. How did you choose your specialty of science, why did you pursue it?

Hi, can anyone give advice on whether I should switch my major from chemistry to physics? I'm not the best at physics, so will it be too hard? Does physics get significantly harder in upper years? If you put in the work and effort to keep up with the classes, is it possible to do well? Or is...

Not sure if this is the right section to post this.. I have 3 measurements and was trying to take the average of the measurements and calculate the error of the average: replicate 1 = 8.9 (+/-) 0.71mg replicate 2 = 9.3 (+/-) 0.69mg replicate 3 = 8.8 (+/-) 0.70mg I get an average of 8.9333...

Not sure if this is the right section to post this.. I have 3 measurements and was trying to take the average of the measurements and calculate the error of the average: replicate 1 = 8.9 (+/-) 0.71mg replicate 2 = 9.3 (+/-) 0.69mg replicate 3 = 8.8 (+/-) 0.70mg I get an average of 8.9333...

Homework Statement How do you solve cosx=-cos2x? The Attempt at a Solution I've tried graphing it, but just wasn't able to crack the solutions Thanks for help!

Homework Statement I'm having problems understanding what F(x,y,z)=k means. What does "it is a level surface of a function F of three variables" mean? If it's a surface, why not describe it as z=f(x,y)? Thanks

Homework Statement So the example says fx(0,0)=0 and fy(0,0)=0 (the partial derivatives). When I try it I'm getting functions that are not defined at (0,0): f(x,y)=xy/(x^{}+y^{}) so for example, fx=[x(x^2+y^2)-2y(xy)]/(x^2+y^2)^2 fx=(x^3+xy^2-2xy^2)/(x^2+y^2)^2...

Homework Statement http://i.imgur.com/F6qLL.jpg In the example, it says if the approaching path of the limit is y=x^2 and x=y^2, the limits are 0. I can see the limit is 0 for approaching in the path of x=y^2 since the function becomes f(x,y) becomes f(y^2,y)=3y^5/(y^4+y^2) \rightarrow 0 as...

Homework Statement In this example, the range is stated to be z=[0,3]. It shows 9-x^2-y^2<=9 which implies sqrt(9-x^2-y^2)<=3 But why don't we consider -3 as well? Thanks

Ohh, I get it now. I wasn't thinking of it the way you have it in the bold. Thanks!

How is |r(t)| not equal to a constant for r(t)=<t,t>? Thanks for replying!

Homework Statement http://i.imgur.com/6j8W6.jpg I'm trying to understand that example in the text. I can imagine a curve on a sphere having the derivative vector being orthogonal to the position vector. What I don't understand is, how does "if a curve lies on a sphere with center the origin"...