Lv 2856 points

# John C

• ### Some sort of portable water heater?

I'm pretty sure something like this does exist but I haven't been able to find it: I'm looking for some sort of coffee mug or travel cup-like container that can heat water with power from a wall outlet. My goal here is to find something that will allow me make tea in my dorm room without using a hot plate or stove (the school considers them a fire hazard). Is anyone aware of such a device? links would be helpful

• ### Calculus: volumes by slicing?

Having some trouble understanding how to find the volume of this solid:

Whose base is the region bounded between the curves y=x and y=x^2, and whose cross sections perpendicular to the x-axis are squares

an explanation of how to set up the integral is really all i need

• ### How do I differentiate this (calculus)?

I'm having trouble differentiating this equation:

find dy/dx

y = 2^x (inverse sec(x^2))

• ### What is the proper format for the Common Application Essay?

I'd prefer that someone who has actually sucessfully submitted a common app essay in their academic career answer this question, though I suppose if you really think you know what you're doing you could give it a shot.

I am wondering if the document needs to be in proper MLA format. Does my paper need a title and my name on top? Proper MLA format requires double spacing, 1" margins, a title, a name section, and page numbers. Should I include all of those, and if not which ones should I include? Or does it not matter?

• ### What is Sammy Stephens' email address?

I'm looking for the email address of Sammy Stephens, of Flea Market Montgomery fame. If anyone knows what it happens to be, I can't find it on the store website.

• ### Calculus trouble, can anyone help?

Not really sure how to get going on this one:

Given: g(x) = (4x+6)f(x) , f(3) = -3 and fprime(3) = 10 Find gprime(3)

would appreciate some explanation from anyone who thinks they want to take a crack at it.

• ### Why is water an ideal medium for biological systems?

What about water's molecular behavior makes it the optimal substance for supporting life?

• ### Lens hood confusion?

I have a canon 28-200mm f/3.5-5.6 for my rebel xti and I was looking to buy the lens hood for it, which supplied by canon is the EW-78D. However, I would like to avoid paying the premium that canon charges (like 40 bucks) for this 3 ounce petal-shaped piece of plastic and buy a generic one instead. I haven't been able to find a reasonably priced generic version but have come across the EW-78B II which is designed to fit the canon 28-135mm IS. Now the question: Does the 78 in the model name signify that this hood is 78mm in diameter, and if so will it fit my 28-200? The 78B does appear to be slightly longer than the 78D and I am wondering if that is the only difference.

• ### Solving Trigonometric Equations?

Having trouble with a few questions that I was given:

Solve:

cos6x - cos3x = 0

Solve, x is between 0 and 2pi

cos2x + sin^2x = 0

4tan^2x - 12tanx + 9 = 0

• ### A trigonometric identity crisis?

Having trouble figuring out a few trig identity problems I was given to do, could use some help.

Given csc = -5/3, A in quadrant III, and cos B = -3/5, B in quadrant II evaluate the following:

1. cos (A+B)

2. cot 2A

Prove each identity:

1. tan(B/2) = cscB - cotB

2. [sin(2a) + sin(6a)] / [sin(10a) - sin(2a)] = cos(2a) / cos(6a)

Express 2sin((5pi)/(12)) sin(pi/3) as a sum

• ### Math help understanding trigonometric identities?

I am having real difficulty figuring out how to simplify these identities, i'll be impressed if anyone can do them.

1. [(sec y-tan y)(sec y+ tan y)]/ sec y

2. [(sec^2 y)(csc y)] / [sec^2 y + csc^2 y]

Also verfying these:

1. (xsina + ycosa)^2 + (xcosa - ysina)^2 = x^2 + y^2

2. [(tan x) / (1- cot x)] + [(cot x) / (1- tan x)] = 1 + (sec x) (csc x)

• ### What is the significance of using the variables h and k in mathematic formulas?

For example, the equation of a circle is (x-h)^2 + (y-k)^2 = r^2

I understand that the variables h and k in this equation signify the center of the circle at point (h,k). However, I would like to know the historical significance of using the letters h and k over other variables. My math teacher did not know the answer and I was interested.

• ### Is it legal to rock climb on highways?

Often when I am on highways and other roads in the New York/ New Jersey area, I will see very large slightly angled rock faces with many holds that would be really cool to climb. Does anyone have any idea if it would be legal to climb these, as I would imagine that they are government property?

• ### Where can I learn how to say some common skiing terms in spanish?

I am going snowboarding in Chile this summer and I speak a little bit of spanish. I was trying to find somewhere online that would have a list of common words that would be used skiing/snowboarding with a spanish translation. Words like mogul, snow, powder, fresh snow, terrain park, chair lift, run, trail, expert, novice, chute, etc. If not can anyone give me their own translation of anything they think would be useful.

• ### Has anyone read "The March" by E.L. Doctorow?

I have to write a 5 paragraph response to this question and I have no clue what to say:

"A dynamic character is one who changes over the course of a work, a static character is one who stays the same throughout. Choose a character from "The March" and argue whether they are a dynamic or static or some combination. Be sure to use examples regarding how they do or do not change."

• ### The Mexican War: "The most unjust war the U.S. has ever fought!" True or false?

Support your answer. I'm interested because I can't decide for a paper I am writing.

• ### How much does it cost to fix a minor dent?

My friend who just got his license bumped into a guardrail in his car leaving a slight dent about the size of an orange no deeper than a 16th of an inch or so on the front section of the front passenger door. It was only on the door and did not cover the space between the door and the frame. My friend refuses to let me open the door because he believes that each time it is opened, the dent will gradually become bigger. I have never heard of this happening, but I could be wrong. Can that kind of thing actually happen and how much would it typically cost to have something like this repaired at a decent body shop without getting ripped off?

• ### Is my memory card speed sufficient?

Is a 4gb memory card at 45x write speed fast enough for my Rebel XTi that shoots 3 fps at 10.1 megapixels? I just bought it without checking the speed (idiot) and am now wondering if I should return it and buy the step up which is about triple the speed for only a few more dollars. Is this lack of speed going to be noticeable when shooting at maximum capacity?