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# Robbie

• ### What would the unit be for the derivative (rate of change) of electrical current?

The question asks: A voltage V across a resistance R generates a current I=V/R. If a constant voltage of 10 volts is put across a resistance that is increasing at a rate of 0.3 ohms per second when the resistance is 6 ohms, at what rate is the current changing? I found the derrivative to be I=-V/R^2 (dR) and am unsure about the units. would it be 1/(ohm x s)?

• ### what are the minimized surface dimensions?

A box has a bottom with one edge 8 times as long as the other. If the box has no top and the volume is fixed at V, what dimensions minimize the surface area? Your answer may involve V.

• ### How to maximize this perimeter?

Consider a window the shape of which is a rectangle of height h surmounted by a triangle having a height T that is 0.8 times the width w of the rectangle. If the cross-sectional area is A, determine the dimensions of the window which minimize the perimeter. h=? w=?

• ### How do you maximize the volume of a cylinder inside a hemisphere?

A hemisphere of radius 1 sits on a horizontal plane. A cylinder stands with its axis vertical, the center of its base at the center of the sphere, and its top circular rim touching the hemisphere. Find the radius and height of the cylinder of maximum volume.

• ### Is 7 inches just "ok", or really big for a penis?

So I know 7in is well above average, but the average is different seemingly everywhere you read about it. Anywhere between 5 and 6.5 is "the national average". My girlfriend thinks my penis is basically average size even though its 7 inches, because the other guy she was with was "a good 8 inches". It doesn't seem fair that her definition of size is skewed but I always thought 7 inches was pretty substantial. is it? While many girls say size doesn't really matter, it definitely does to her.

• ### How do I find d^2x/dt^2 as a function of x if dt/dx=xcosx ?

I thought I would just take the derivative of xcosx, which end up being cosx-xsinx . However, the computer says that answer is incorrect.

• ### What is a purpose statement and should I use one, or should I use an if-then statement?

I am doing a lab report and the instructions tell me that "If the lab is one of finding a value then a PURPOSE statement should be used in place of a hypothesis". The lab was to determine/verify the optimum launch angle for a projectile to produce a maximum distance (obviously 45 degrees). We shot metal balls out of a spring loaded launcher and landed them on carbon paper, and measured the resulting distances.

knowing this, should my hypothesis be an if/then statement, or a purpose statement, and if it is in fact a purpose statement, what should it look like?

1 AnswerOther - Science9 years ago
• ### Does anyone know the name of this "scientific" search engine I'm describing?

In my precalc class, our teacher sometimes uses this search engine where you can for example type in x^3+5x^2+7x-2 solve for x and it will solve for x and show all the steps so if you don't know how to do something, it will help immensely considering we have a test monday. This search engine will search for anything not just math, for example you can search a movie and find the actors in it and everything. I cannot remember the name of this website just that is said "scientific search engine" at the top and the name of the website was some name of a person like wilfredmathus.com or something.

• ### How do i stop my outdoor faucet from running?

Yesterday i turned my outdoor faucet, that was hook up to a hose, on to water some plants. when I was done i went to turn the faucet off and it was really hard to turn and i got it most of the way. At this point it is seemingly impossible to tighten it any more. water still comes out of it in a small steady stream, filling up a large bucket every 25 minutes or so. how should I go about fixing/ stopping this and should i be concerned about damaging the foundation of my house because the ground area around the faucet is decently wet.