Science & Mathematics - 2 December 2007

Help is greatly appreciated. I'm not sure how to do these problems. Help in steps please. The (i) is not under the radical.

1.) (1 + √7i)(-2 - √5i)

2.) (2 + √-3)(-1 + √-12)

3.) Write an equation with solutions i and -i

Thanks everyone!

2007-12-02 12:59:41 · 1 answers · asked by deb3267 1 in Mathematics

2007-12-02 12:55:53 · 5 answers · asked by Peter N 2 in Biology

2007-12-02 12:53:36 · 15 answers · asked by Blackie . 1 in Parapsychology

I really don't get this one problem can anyone help?
Plz xplain ty for your help

2007-12-02 12:52:13 · 5 answers · asked by MiCk 2 in Chemistry

the problem was

63c2-7(the 2 is an exponent)
then i could see you can take 7 out of both of those so i did.
63c2/7 - 7/7
and put whats left in parenthesis
7(9c2) (once again 2 is an exponent)
then i factored it completely and got this
7(-9c)(+9c)


it doesnt seem right. help me please. =]

2007-12-02 12:50:09 · 4 answers · asked by Anonymous in Mathematics

A 3.10 kg block is pushed along the ceiling with an constant applied force of F = 86.5 N that acts at an angle = 52° with the horizontal, as in the figure below. The block accelerates to the right at 6.02 m/s2. Determine the coefficient of kinetic friction between the block and the ceiling.

and

A clerk moves a box of cans down an aisle by pulling on a strap attached to the box. The clerk pulls with a force of 184.0 N at an angle of 30° with the horizontal. The box has a mass of 31 kg, and the coefficient of kinetic friction between the box and the floor is 0.45. Find the acceleration of the box.v

2007-12-02 12:50:00 · 1 answers · asked by Anonymous in Physics

Why should space-time have an overall shape, such as being positively curved (like a sphere), negatively curved (like a saddle), or flat (like a perfect plane)?

2007-12-02 12:47:59 · 5 answers · asked by Anonymous in Astronomy & Space

Please help me!!!!!!!!!

2007-12-02 12:44:50 · 2 answers · asked by Victoria B 2 in Chemistry

A clothesline is under tension when you hang from it. Why is the tension greater when the clothesline is strung horizontally than when it hangs vertically?

2007-12-02 12:44:34 · 1 answers · asked by Anonymous in Physics

2007-12-02 12:42:40 · 12 answers · asked by Anonymous in Astronomy & Space

what would you rather prefer, -35 degrees Fahrenheit with 2 feet of snow or 135 degrees with 100% humidity?

2007-12-02 12:39:01 · 8 answers · asked by Anonymous in Weather

i really want to on and why i searchd and cant ifnd the answer, i dont want opinions just facts

2007-12-02 12:35:49 · 5 answers · asked by dts 2 in Zoology

it started out as 1x3-4x (the 3 is an exponent)
and i know you can take x out of both of those so i did this
1x3/x - 4x/x
and then i got to re write whats left with the x on the outside of the parenthesis.
x(????)

thats as far as i got :P help please!

2007-12-02 12:35:03 · 4 answers · asked by Anonymous in Mathematics

divide and simplify

2007-12-02 12:34:48 · 4 answers · asked by shakelia 1 in Mathematics

I have this huge math project due for thursday about everything I learned math-wise so far in my life. I know of sin^(-1) (or asin) and cosec (csc) which is 1/sin. Since x^(-1) = 1/x, is sin^(-1) = 1/sin? If so, it would mean that sin^(-1) and cosec would both be the same thing right? Furthermore, I don't know how to label those functions. I would call them inverse functions but they would both have the same name. So, basically, are sin^(-1) and cosec the same? If not, how would you label them? Thanks, Seb

2007-12-02 12:34:29 · 1 answers · asked by Seb 1 in Mathematics

Please tell me the answer and explain how you got it.

2007-12-02 12:30:44 · 8 answers · asked by vintagelove 2 in Mathematics

2007-12-02 12:30:37 · 5 answers · asked by Silent Gams 5 in Medicine

2007-12-02 12:27:20 · 4 answers · asked by Anonymous in Geography

2007-12-02 12:27:07 · 4 answers · asked by Anonymous in Mathematics

When a certain metal is illuminated with light of frequency 3x1015 Hz, a stopping potential of 5.5 V is required to stop the ejected electrons. What is the work function of this metal in eV ?(Notice that the stopping potential is the potential difference required to bring the electrons with the maximum kinetic energy to a complete stop.)


The answer is in eV

please help me...................... =(

2007-12-02 12:26:28 · 1 answers · asked by Anonymous in Physics

anthony and sara are participating in the "Roll-a-Roma" rollerskating dance championship. While 75 kg Anthony rollerskates backwards at 3 m/s, 60 kg Sara jumps into his arms with a velocity of 5 m/s in the same direction

a). how fast does the pair roll backwards together?

b). If Anthony is skating toward sara when she jumps, would their combined final velocity be larger or smaller than your answer to part A?

2007-12-02 12:24:55 · 1 answers · asked by kiwi 1 in Physics

2007-12-02 12:23:57 · 8 answers · asked by ♥Ebonique♥ 2 in Mathematics

(You may or may not need all of the reactions, #1-3.)


Eq. #4 4 CO2 (g) + 6 H2O (g) → 2 C2H6(g) + 7 O2(g)
________________________________________

Eq. #1 C2H6(g) → C2H2(g) + 2 H2(g)
ΔH = 189 KJ

Eq. #2 C2H2(g) + 5/2 O2(g) => 2 CO2(g) + H2O(g)
ΔH = - 470 KJ

Eq. #3 H2O(g) => H2(g) + ½ O2(g)
ΔH = 142.5 KJ

Im totally lost. I hope you guys can help. Please explain how you arrive at the answer. I'd like to KNOW how to do this, rather than just simply have the answer. THANKS

2007-12-02 12:21:16 · 1 answers · asked by Charles Gerald S 1 in Chemistry

2007-12-02 12:18:57 · 2 answers · asked by anonymous 3 in Mathematics

Can you please help me to understand this, or at least give me the answers?

"A test is carried out to determine the presence or absence of the ions that are listed. State if the test results indicate if each possible ion is present, absent, or undetermined."

1. Test for Ag+, Cu^2+, Fe^3+
Some 6 M HCl is added to a solution that may contain the three ions. A white precipitate forms.

2. Test for Mn^2+, Fe^3+, Cu^2+
Some 3% H2O2 and 6 M NaOH are added to a pale blue solution. A dark precipitate forms, which totally dissolves when 6 M H2SO4 is added. Addition of 6 M NH3 to the solution until it is basic results in a deep blue solution containing a dark precipitate. The dark precipitate completely dissolves in H2SO4.

There are 4 more, but if I post them all you guys probably won't answer! haha. thanks in advance for the help.

2007-12-02 12:18:29 · 1 answers · asked by missingfeet 2 in Chemistry

2007-12-02 12:18:11 · 3 answers · asked by Patrick W 2 in Zoology

2007-12-02 12:14:41 · 10 answers · asked by skylar b 1 in Geography

1. The sum of two negative numbers is greater than either number.

2. The sum of two positive numbers is greater than either number.

2007-12-02 12:13:12 · 3 answers · asked by Anonymous in Mathematics

If Leah is 6 years older than her sister, Sue, and John is 5 years older than Leah, and the total of their ages is 41. Then how old is Sue?

i get so confused with these questions..please explain

2007-12-02 12:13:00 · 5 answers · asked by Anonymous in Mathematics

2007-12-02 12:12:09 · 6 answers · asked by fatgut1210 1 in Astronomy & Space