Mathematics - 16 December 2007

not sure how to solve this? any help is appreciated!

Solve the system of equations.

2x-2y+4z=2
4x+2y-2z=-10
6x+4y-2z=-16

2007-12-16 05:43:55 · 10 answers · asked by Anonymous

I have 2 questions that I cannot understand. Help is greatly appreciated.
1)Physics:Uniform Motion-
A motorboat maintained a constant speed of 15mph relative to the water in going 10miles upstream and then returning.The total time for the trip was 1.5 hours.Use this information to find the speed of the current.
2)Computing Average speed
In going from Chciago to Atlanta, a car averages 45mph and in going from Atlanta to Miami, it averages 55mph.If Atlanta is halfway between Chicago and Miami,what is the average speed from Chicago to Miami? Discuss an intuitive solution. Write a paragraph defending your intuitive solution.Then solve the problem algebraically.Is the intuitive solution the same as the algebraic one?If not find the flaw.
Thanks in advance for any help.

2007-12-16 05:38:14 · 2 answers · asked by terrible at pre-calculus 2

how do you know to use the uniform distribution and why is the distribution of U(-0.5,0.5) ?

In a laboratory, 48 measurements are taken and rounded off
to the nearest integer. Find the probability that the total error
introduced by rounding is no more than 2.

2007-12-16 05:32:43 · 1 answers · asked by Anonymous

im so confused with my homework !
How is it that
sec( - theta) = - csc theta ? ? ?
and how does
cot ( pi + pi/4) = 1??
i am really confused!! can anyone help??

2007-12-16 05:22:07 · 6 answers · asked by Anonymous

2007-12-16 05:19:16 · 4 answers · asked by Anonymous

its for my math homework and im stuck, please help

2007-12-16 05:19:00 · 5 answers · asked by Anonymous

I want to purchase a hands free magnifier such as Optiviewer or Magniviewer and they are described as 6", 8", 12" with a related diopter number. How do I select one of these?

2007-12-16 05:12:57 · 2 answers · asked by Jack W 1

4q(3p^2-5q)(3p^2+5q)
The numbers after the "^" are powers.

I got the answer 36qp^3-100q^3

2007-12-16 05:12:00 · 5 answers · asked by Anonymous

What is the absolute value of 0/2

2007-12-16 05:11:34 · 4 answers · asked by Fel 2

i am stuck with the follwoing question: floor is 2.4m by 1.6m. all the tiles are 20cm cquare. one layer of border tiles is placed around the edge. how many tiles are needed to fill in the middle?

2007-12-16 05:02:44 · 5 answers · asked by Tin T 2

Hi there,
I'd like to ask for an explanation on finding positive and negative coterminal angles of both degrees and radians. For example, how would I find the two for something such as -230 degrees, or 23(pie)/6? Any helpful explanations will be greatly appreciated. Thanks!

2007-12-16 04:59:22 · 4 answers · asked by Quasar 2

"Ask Marilyn"

2007-12-16 04:56:40 · 2 answers · asked by jimmymae2000 7

Find the slope of any line perpendicular to the line through points (6, 3) and (7, 7).

2007-12-16 04:47:55 · 7 answers · asked by mrsstrick27 2

2007-12-16 04:43:40 · 14 answers · asked by Anonymous

how can you prove that 4 points on a line are collinear?

I need 3 methods

2007-12-16 04:42:36 · 2 answers · asked by xoxox 2

I need to know the steps involved in doing this problem please. This is what i have, tell me if its right and what comes next.
77=10log(sub 10) (s/10^-12)
7.7=log(sub10) (s/10^-12)
10^7.7=S/10^-12
10^7.7 * 10^-12=S


I know the answer is 5.01 * 10^-5 but i dont know how to get there.

Thanks!!!

2007-12-16 04:24:56 · 2 answers · asked by Anonymous

30(10-5)-4(12-5)
_______________

10 I2-6I -2(5+2)

the I I means absoute value.

2007-12-16 04:12:42 · 3 answers · asked by Anonymous

[7(6-9)-2]-[4-(7-3)]

2007-12-16 04:08:17 · 4 answers · asked by Anonymous

Can you help me with these problems below? There are inequalities. please only answer if you know what u are talking about. this is due tomorrow. Thanks! (sorry the negative/subtract signs are so small) There are 3 problems. THANK-YOU!!!!!!

-5(q+12)<3q-4

7(g+8)<3(g+2)+4g

-5x+3<3x+19

2007-12-16 04:07:57 · 2 answers · asked by funkymonkey6248 2

how do i evaluate 905^2 - 95^2 using suitable algebraic rules?
what about 38*62+38^2 and 69*45+45*31

2007-12-16 04:07:21 · 4 answers · asked by korean_freak_ruii 3

assuming the least upper bound property, how can we prove the nested intervals property?

2007-12-16 03:57:14 · 1 answers · asked by Ben F 1

2007-12-16 03:48:15 · 8 answers · asked by Anonymous

In miles per hour... How fast is 300km? What is the scale used to determine it?

2007-12-16 03:44:00 · 5 answers · asked by null 4

Ind. Int.="Indefinite Integral"
In my book (Stewart) they say

"Recall that the most general antiderivative on a given interval is
obtained by adding a constant to a particular antiderivative. [Bold]We adopt the convention that
when a formula for a general Ind. Int. is given, it is valid only on an interval.[/Bold] Thus, we write

Ind. Int. 1/x^2 dx = - (1/x) + C

with the understanding that it is valid on the interval (0, infinite) or on the interval (-infinite, 0). This is true despite the fact that the general antiderivative of the function , f(x)=1/x^2, x ≠ 0 , is:

F(x):
- (1/x) + C1 if x<0
- (1/x) + C2 if x>0"

Well, I don't understand this convention, don't know if it is something too obvious and I'm complicating myself, like, "there could be points where the Ind. Int. isn't defined" or maybe there's a subtle point behind this, maybe they want to say that a Ind. Int. that holds for any interval, no matter how small, it's a valid Ind. Int of the function.
Thank u.

2007-12-16 03:31:08 · 2 answers · asked by andacecha 2

2007-12-16 03:19:00 · 5 answers · asked by Anonymous

we are looking at snow board need size

2007-12-16 03:08:11 · 9 answers · asked by Anonymous

Prove that csc 0 is undefined

&

A sector of a circle has a central angle of D degrees. Prove that the area of the sector is A=(1/2)r^2R where r is the radius and Ris the Radian Measure


Thank you

2007-12-16 02:52:16 · 4 answers · asked by Megan Myers 1

How much water should be aded to obtain a solution that is 60% antifreeze?

.6x-.6=40
.6x=1
x=1/6?

2007-12-16 02:51:42 · 4 answers · asked by Anonymous

girl is 3 years younger than the boy the product of theri age is 238.

PLease help.

2007-12-16 02:44:17 · 15 answers · asked by shamini 1

2007-12-16 02:28:28 · 8 answers · asked by Hyumby 2