Mathematics - 18 November 2007

2007-11-18 23:29:33 · 2 answers · asked by youngmoigle 5

If the solid plane parallel to and 6 inches from the base of the pyramid makes a section with an area 18.5 square inches. Find the altitude of the pyramid.

2007-11-18 23:16:25 · 2 answers · asked by exilimo 1

4x-y²=-1
x-y=5

2007-11-18 23:05:52 · 10 answers · asked by Wasif 2

2007-11-18 21:58:55 · 2 answers · asked by toddinav 1

2007-11-18 21:47:34 · 4 answers · asked by toddinav 1

i am studying for a test and cant figure out this question:
if y=(2x-1)^4, prove:
d/dx (y* dy/dx) = y * (d^2*y) / dx^2 + (dy/ddx)^2

hope that makes sense
thanks in advance

2007-11-18 21:26:39 · 5 answers · asked by Anonymous

2007-11-18 20:34:10 · 2 answers · asked by alborz a 1

On its banner the other day Yahoo threw bouquets at Alexis Lemaire for a new world record in calculating the 13th root of a 200 digit number in 72 secs. With a computer.
In 1977, Shakuntala Devi extracted the 23rd root of a 201 digit number mentally. In 1980 she mentally multiplied two 13 digit numbers in 28 secs. Her answer was 18, 947, 668, 177, 995, 426, 462, 773, 730.

2007-11-18 20:29:43 · 2 answers · asked by virtrava 3

How it came to b in used in all meansuration calculations??y its value id fixed?

2007-11-18 20:20:28 · 13 answers · asked by Anonymous

heyy everyone!!! HOW DO U CHANGE A DECIMAL INTO A FRACTION???????

2007-11-18 20:12:59 · 5 answers · asked by Anonymous

is saying x is directly propotional to y the same as saying x=y?

2007-11-18 18:48:26 · 4 answers · asked by Omar 1

Okay so here's how it's going down:
I need to know how to split a single pentagon into five congruent parts in three different ways.
I also need to know how to split a hexagon into six congruent parts in three different ways.
I'm screwed if I don't find out soon so....
Thanks so much all you mathies!!! I really respect you!

2007-11-18 18:40:59 · 3 answers · asked by Anonymous

differentiate the function:
f(u)= ln u / (1+ln(2u))

The answer is f'(u)= (1+ln2) / u(1+ln(2u))^2
but I have no idea how to get it!! Thanks!

2007-11-18 18:33:17 · 2 answers · asked by Anonymous

The apothem of a regular pentagon is 10.8 centimeters.

a) Find the radius of the circumscribed circle.
b) What is the length of a side of the pentagon?
c) Find the perimeter of the pentagon.

2007-11-18 18:24:07 · 1 answers · asked by Roy Poomiwatracanont 1

2007-11-18 18:12:42 · 2 answers · asked by W.C.Y90 2

Log 10^-7 = x.?
Does x = 1 or
Does x = -7 ?
Or something else?

2007-11-18 18:03:39 · 8 answers · asked by Jeremy B 2

the question is :
determine whether the series is absolutely convergent, conditionally convergent, or divergent

http://i181.photobucket.com/albums/x85/ctti_3/1195433439Xuj_Page_4-1.jpg

2007-11-18 17:01:02 · 2 answers · asked by ruby 2

25v^2+60v+27

2007-11-18 16:47:25 · 4 answers · asked by Anonymous

If they exist, find the x, y, and z intercepts of the line x=24+7t, y=4+t, z= -20-5t.

(the answer to this was that the x intercept was -4)

how do i get to the answer?

2007-11-18 16:43:46 · 4 answers · asked by internet nickname 1

Here's a fun one: it is possible to divide a (circular) pizza with n cuts into more than 2n pieces (not necessarily equal, and the cuts do not all go through the center or bisect the pizza).

- the ordinary way, n cuts all through the center gives 2n uniform pieces and it is trivial to make them equal size.

However the MAXIMUM number of pieces p(n) for n cuts is called the lazy caterer's sequence and goes like this: 1, 2, 4, 7, 11, 16, 22, 29...
See e.g. the Wikipedia picture of the pancake cut into 7 pieces by 3 cuts (the middle piece is a (possibly equilateral) triangle)
http://en.wikipedia.org/wiki/Lazy_caterer%27s_sequence
Note: "equal-area" does NOT imply "uniform"!

So anyway my questions are these:
a) for n cuts, define the general algorithm to make the cuts
b) what is the ratio r(n) of largest to smallest pieces area?
Try e.g. computing r(3) and r(4)
c) is there a more useful sequence of cuts such that 2n

2007-11-18 16:41:24 · 2 answers · asked by smci 7

thanks if you can help.

(3) superscript -2x = ( 1/5) timesx (27) superscript x

the 3 is in parenthesis the negative 2 x is superscript =equals= one fifth in parenthesis times 27 in parenthesis with x as a subscript.
ahhhhhhhhhhhhhhhhhhhhhhhhhhhhh thanks

2007-11-18 16:31:39 · 4 answers · asked by Boo Radley 4

say heat flow is being modelled by the temperature in the xy-plane is given by:
T(x,y)=x*y - x

I've found the general directional derivative at the point (2,2), and the direction that temperature changes most rapidly from there, and now i'm being asked this:

If heat flow is a direction -∇T, express this as a differential equation in y and x and solve it. I'm sure I could solve it but I don't understand how you find the differential equation. how do you express it as one?

please help!

2007-11-18 16:30:29 · 1 answers · asked by mongrel73 1

I do an online program and i am a senior in high school. With this program I have no teacher and I get no practice. I am doing functions but have no clue how to do some. How do you do these?
1. f(x) = x2 + 7x
Find f(-3)

2. f(x) = -3x + 9
g(x) = 8x + 7
Find f(x) + g(x)

3. f(x) = -3x + 9
g(x) = 8x + 7
Find f(g(x))

4. f(x) = 4xSquared
h(x) = -7x - 5
Find h(f(3))

5. h(x) = 2x3 - 5x2
Find h(3)

6. h(x) = 2x3 - 5x2
Find h(-5)

7.f(x) = 15 - 6x
g(x) = 3 x
5
Find g(f(x))

8. f(x) = x3 - x2 - 3x + 5
Find f(4)

THANK YOU FOR ANY HELP THAT YOU CAN GIVE ME. I GREATLY APPRECIATE IT.

2007-11-18 16:17:10 · 6 answers · asked by Anonymous

?

2007-11-18 16:07:27 · 3 answers · asked by Anonymous

the equation is y = 3/4x + 5/2

2007-11-18 15:25:47 · 11 answers · asked by Donovan Rose 1

An infinite rod with initial temperatures f(x) = A when x>0 and f(x) = B when x<0. Find the temp u(x, t) for time t>0 expressed in terms of the error function

2007-11-18 15:20:56 · 1 answers · asked by Anonymous

2007-11-18 15:14:38 · 2 answers · asked by Selena T 1

2007-11-18 15:04:01 · 6 answers · asked by vsmooth8 1

2007-11-18 15:03:42 · 3 answers · asked by Anonymous

Okay, I've been doing a review sheet for my pre-calc final and I've been able to do most of these problems okay. (Albeit it takes me awhile sometimes, lots of trial and error.)

However out of all of them these five gave me the most trouble, in the section of verifying trigonomic identities, if anyone knows how to work these out in steps I'd be greatly appreciative to know.

Anyhow here they are:

1.) sec^4 - tan^4x = sec^2x = tan^2x
2.) cos θ (sec θ - cos θ) = sin^2 θ
3.)
(sinx + cosx)^2 / sin^2x-cos^2x = sin^2x - cos^2 / (sin x - cos x)^2
(I think I'm doing this one correctly but I am still curious about it.)

4.)
(cotx - cscx)^2 = 1-cosx / 1+cosx

5.) (3cos θ - 4 sin θ)^2 + (4cos θ + 3 sin θ)^2 = 25

Any help would be great!

2007-11-18 14:56:12 · 3 answers · asked by Disasterpiece 1