Mathematics - 14 September 2007

How many common tangents do teo circles x^2+y^2+2x-6y-26=0 & x^2+y^2-4x+2y+4=0 have?

2007-09-14 21:48:49 · 1 answers · asked by Anonymous

1. x^3-36x

2. x^2+x

2007-09-14 20:34:03 · 3 answers · asked by Anonymous

Here's what I've done so far:

(8+x^3)(8-x^3)
(2+x)(4-2x+x^2)(2-x)(4+2x+x^2)
Can it be further factored?

Thanks all in advance!

2007-09-14 19:26:44 · 9 answers · asked by Anonymous

Solve the following equations using either the quadratic formula or by completing the square.Give your answers to 2 d.p.

x2-35=0

and also
x2-3x-3=0[am i supposed to use the square for this?how exactly do you do this?]

I know im prob sposed to work these out myself but they're during tmr and im really stuck!
its one of my GCSE practice questions.There are bout 20 more but I just need to know the basics in order to do the rest.
thanks a mill.

Luvv,
Kris.

2007-09-14 18:55:30 · 6 answers · asked by krystal_engel 3

As far as I know, no one knows why "m" and "b" are used.

2007-09-14 18:34:21 · 7 answers · asked by discover425 2

2007-09-14 18:32:47 · 7 answers · asked by Anonymous

The Heaviside function H is defined below. It is used in the study of electric circuits to represent the sudden surge of electric current, or voltage, when a switch is instantaneously turned on. The Heaviside function can also be used to define the ramp function y = ctH(t), which represents a gradual increase in voltage or current in a circuit.

http://www.webassign.net/www30/symImages/e/b/7b468910ea394002f905894a548898.gif

as seen in above link, H(t)={ 0 if t<0, 1 if t> or = 0

(a) Write a formula for V(t) in terms of H(t) if the switch is turned on at time t = 0 and the voltage is gradually increased to 140 volts over a 70 second time interval.

(b) Write a formula for V(t) in terms of H(t) if the switch is turned on at time t = 6 seconds and the voltage is gradually increased to 220 volts over a period of 55 seconds.

2007-09-14 18:29:55 · 1 answers · asked by ILuvTaraReid 2

2007-09-14 18:13:33 · 9 answers · asked by Anonymous

Needs to solved in terms of ln, natural log

2007-09-14 18:03:00 · 4 answers · asked by Kelli J 2

math whiz

2007-09-14 17:49:16 · 19 answers · asked by football player 3

3. The germination rate for zinnia seeds is 78%. This means that, on average, 78% or the seeds will sprout and grow into plants.

Q: What is the independent variable? What is the dependent variable?
A: independent: germination rate
Dependent: seeds

Q: Express this relationship as a function.
A: f(x) = .78x

Q: What is the domain of this function? What is the range?
A: x is greater then or equal to zero
Y is greater then or equal to zero
Q: If Jim wants 60 plants for his yard, how many seeds should he plant?
A: x = 77

4. It costs $25 a day plus $.06 per mile to rent a car.
Q: What is the independent variable? What is the dependent variable?
A: independent: days
Dependent: cost

Q: Express this relationship as an equation.
A: f(x) = 25x + .06

Q: What is the domain of this function? What is the range?
A: x is greater then or equal to zero.
Y is greater then or equal to .06

Q: What is the greatest number of miles you can drive in a day if you have $40
A: x = 1.5976

2007-09-14 17:45:22 · 2 answers · asked by Ryoma Echizen 3

3/4 - 2/3 > -x/6 ( both the numerator and denomentator are negative.)

2007-09-14 17:40:57 · 3 answers · asked by Anonymous

1. The sum of the digits of a two digit number is 14. if the digits are received, the number is increased by 18. What is the number?

2. One number is 4 less than another number. The sum of the numbers is four times their difference. What are the two numbers?

3. How many kilograms of pure silver must be added to a 60% silver alloy to obtain 8 kilograms of a 57% silver alloy?

4. How many liters of a 35% acid solution should be mixed with a 14% acid solution to obtain 70 liters of a 20% acid solution?

5. Mr. Santos purchased 10,000 worth of stocks. One stock pays dividends at the rate of 4% per year. The other stock pays 6% per year. If Mr. Santos’ yearly income from the dividend is 500, how much of each stock does he own?

6. Cashing a check of 4000, Mrs. Cruz asked for the whole amount in 50 and 100 bills. She received a total of 53 bills. How many of each bill did she receive?

2007-09-14 17:32:08 · 4 answers · asked by Ruth Naomi Mariae R 2

This has been stumping me.

When a camera flash goes off, the batteries immediately begin to recharge the flash's capacitor, which stores electric charge given by the following. (The maximum charge capacity is M and t is measured in seconds.)
Q(t) = M(1 - e^(-t/a) )

2007-09-14 17:26:01 · 2 answers · asked by ILuvTaraReid 2

I'm currently in a Chemistry class, and one of the things we've learned is rounding numbers to the correct numbers of significant figures. It's easy stuff, so it's not troubling me, but I've just been wondering what the point is in rounding to significant figures. Is there any practical use for it, or did some scientist or whatever one day decide we should do that?

2007-09-14 17:22:16 · 5 answers · asked by chucknorris=theman 2

how to solve this

2007-09-14 17:18:57 · 6 answers · asked by Anonymous

567=7/3q

480=3/7q

164=4/5q

2007-09-14 17:07:04 · 9 answers · asked by finitemathkid 1

From a certain point, the angle of elevation to the top of a church steeple is 10 degrees. At a point 100 m closer to the steeple, the angle of elevation is 20 degrees. Calculate the height of the church.

the answer i got (from using the sin/cos laws) was 34.21 m. can anyone confirm this for me? though my answer probably is wrong anyway . . .

thank you very much!

2007-09-14 16:53:14 · 11 answers · asked by Anonymous

I was absent for this...

2007-09-14 16:16:45 · 12 answers · asked by No Connection 1

I am having trouble figuring out which graph is right, could you guys please tell me which one it is, and explain why its the correct one?
Here is a link to the question and graphs:
http://www.flickr.com/photos/13557617@N03/1383516767/

2007-09-14 15:52:18 · 3 answers · asked by finitemathkid 1

You find 38 coins consisting only of nickels, dimes, and quarters, with a face value of $4.75. However, the coins all date from 1926, and are worth considerably more than their face value. A coin dealer offers you $8 for each nickel, $6 for each dime, and $22 for each quarter, for a total of $410. How many dimes did you find?

2007-09-14 15:23:23 · 2 answers · asked by Anonymous

Can someone explain to me what it is?

2007-09-14 15:05:53 · 6 answers · asked by Jenna 1

The equation of tgeh line through (8,6) and (2,-4) is
choose from the following answers:
a. 5x - 3 = 22
b. y=3/5x+8/5
c. 3x+4y=48
d. =4x+2y= -16

2007-09-14 15:02:33 · 3 answers · asked by Trinity 1

f(x) = (x+2)(2x-3). F(-2) =
choose from the following answers
a. 0
b. 6
c. -6
d. -14

2007-09-14 15:00:00 · 3 answers · asked by Trinity 1

Find the angle (in degrees) between the plane x+6y+z=3 and the line with symmetric equations (1/6)x+(1/2) = y-1 = z-1.

2007-09-14 14:59:12 · 3 answers · asked by Anonymous

Donna invested her $33,000 bonus and received $970 in interest after one year. If part of the money returned 4% and the rest earned 2.25%, how much did she invest at each rate?

2007-09-14 14:58:21 · 3 answers · asked by Mariana C 1

A line passes through A = (1, 4, 1) and is perpendicular to the plane 5x+5y+2z=2.
Find the point P of intersection of the line and the plane.
Thanks for the help!

2007-09-14 14:53:36 · 0 answers · asked by drsayre2002 3

2007-09-14 14:48:47 · 3 answers · asked by fm 1

They are billed a fixed amount yearly plus a charge for each cubic foot of water used. A household using 1000 cubic feet was billed $90, while one using 1600 cubic feet was billed $105.

A. What is the charge per cubic foot?
B. Write an equation for the total cost of a resident's water as a function of cubic feet of water used.
C. How many cubic feet of water used would lead to a bill of $130?

2007-09-14 14:41:47 · 2 answers · asked by Anonymous

A mint has three machines capable of making coins. All three machines together can make 246 coins per minute. Machine A is twice as fast as machine B. Machine C can make 30 more coins per minute than machine B. How many coins per minute can machine B make?

2007-09-14 14:40:19 · 4 answers · asked by Anonymous