Recent content by ktobrien

SS_D 6 is 300 over the square. x goes from 0 to 5 and y goes from x-5 to 5-x. This is half of the square. This integral equals 150. You then multiply that by 2 to get the whole square. The answer is therefore 300. My answer is correct. Also, D is not a 10X10 square. It is a 5X5 square...

Yes. SS_D 6 is also 300. Does this mean my answer is right?

Homework Statement Use symmetry to evaluate the given integral. SS_D 6-x+7y dA where D is the region bounded by the square with vertices (±5, 0) and (0, ±5). Homework Equations Integrals The Attempt at a Solution I worked it out and got 300. But I did it by integrating one half then the other...

Can someone please help me out?

Plugging into the two formulas I got. 3.5e-5(l1) + 1.5e-6(l2) = 9.2363e-5 but this gives me 1 equation and 2 unknowns

Could still use some help. Thanks.

Rho is the resistivity. Alpha is the temperature coefficient. Both values of resistivity are positive as written. Carbons temperature coefficient is positive and nichromes is negative.

Homework Statement An engineer needs a resistor with zero overall temperature coefficient of resistance at 20°C. She designs a pair of circular cylinders, one of carbon and one of Nichrome. The device must have an overall resistance of R1 + R2 = 15.0 Ω independent of temperature and a...

Ive got it now. I used the linear approximation and set it = to 0. I just had to take out the f(5,3,-3). I figured it was something stupid like that. Thanks for the help though.

Homework Statement Find equations of the following. x2-2y2+z2+yz=7, (5,3,-3) (a) the tangent plane (b) the normal line to the given surface at the point Homework Equations I know it involves fx, fy, fz The Attempt at a Solution I got 10x-15y-3z=7. Is this correct? Because its not true at...

Yea that's what I thought. Thanks for confirming that. I just discovered my calculator has been in radians. Thanks.

Homework Statement Suppose you are climbing a hill whose shape is given by the equation below, where x, y, and z are measured in meters, and you are standing at a point with coordinates (120, 80, 1064). The positive x-axis points east and the positive y-axis points north. z = 1200 - 0.005x2...

Thanks a lot. I figured it was something simple like that.

No the other ones are right. I have already checked them. How do I get L to know what to divide by? Do I just plug in the original l w h to find L?

2l(dl/dt)+2w(dw/dt)+2h(dh/dt) for A I got 675m^3/s for B I got 312m^2/s