Mathematics - 2 December 2007

using the formulae d = |OA.OB|

where OA=[1,2,3]
OB=1/6[4,-4,-2]

there are many formulaes i found and im confused, is the answer -5/3(from doing 1X2+2X-4+3X-2...but thats the vector product)??
please show the working ,

2007-12-02 23:58:18 · 2 answers · asked by nack nack 3

A person whose mass is 75 kg is lowered with a rope down the side of a cliff. The rope being used can support a maximum of 595 N. In order to prevent the rope from breaking, at what minimum rate must the person accelerate downward?

2007-12-02 23:57:08 · 8 answers · asked by Anonymous

f(x)=2x²-3x-2=0

by using the discriminant b²-4ac

2007-12-02 23:50:53 · 1 answers · asked by Anonymous

A) The population of China is growing exponentially at a rate of 1.1% per year.
How long will it take China to double its population? _________________

B) The value of the property in S-ville decreases exponentially at a rate of 6.8% annually. The original value of the house was $150,000.
Write the function modeling the value of the house over time.
V(t) = _________________________________

2007-12-02 23:46:33 · 2 answers · asked by momof3 1

(polynomials)

I just want to check if i got the right answer

x^2+3x-18x-40=0

ty

2007-12-02 23:28:46 · 5 answers · asked by xMwahahahahahahax 3

5x-4y=8
6x-y=21
Exactly by analytical means

2007-12-02 23:11:25 · 7 answers · asked by Anonymous

Ln(x³)+3ln(x²)=2

Im completely suck

2007-12-02 22:28:26 · 8 answers · asked by Anonymous

what interest rate is required in order that your money will trible in the next 20 years with semi annual compounding?

could someone please help me with this. thanks.

2007-12-02 22:15:13 · 3 answers · asked by Mathema-what?! 1

Please help me with this problem... Pretty please...

A tree casts a shadow of 42ft. at the same time that a yardstick casts a shadow of 2ft. How tall is the tree?

additional query:
How does the conversion goes again?

Thank you ever so much in advance! God bless! ^^,

2007-12-02 22:13:24 · 8 answers · asked by Anonymous

I dun get this math stuff

explain please so that a 12 year old would understand?

Thankyou.

2007-12-02 22:10:15 · 7 answers · asked by Anonymous

I would usually use my ruler, but my new one doesn't have inches.

2007-12-02 22:03:36 · 10 answers · asked by Anonymous

integral of sqrt(1-x^2)dx
integral of sqrt(x^2-1)dx
integral of sqrt(x^2+1)dx

no formulas...need to prove them :( PLease help its 3:45 am and I've been up all night!

2007-12-02 21:43:06 · 2 answers · asked by cutiemutie9 1

2007-12-02 21:16:25 · 2 answers · asked by Answer Seeker 1

Given that velocity = v(t) = tlnt - t , find the expression (or anti-derivative) for the position x(t).

I don't know how to take the anti-derivative of the tlnt part =\

2007-12-02 21:07:26 · 3 answers · asked by Jessicaaaaa 1

how can i find the dimensions of the lower base of a frustum of a rectangular pyramid if only the volume,height & the dimensions of the upper base are given?

2007-12-02 20:46:32 · 2 answers · asked by mhymhymhymhymhymhymhy 2

When Xn = (n^(-2))*(log(n))^4
How do you work it out?
Thanks.

2007-12-02 20:41:57 · 1 answers · asked by Dave_G 2

A rower travels upstream at 6km per hour and back to the starting place at 10km per hour. The total journey takes 48 minutes. How far upstream did the rower go?

2007-12-02 20:24:49 · 7 answers · asked by Anonymous

parabola y=4-(x)^2 cuts x axis at R and S... P (x,y) lies on parabola in 1st quadrant, and Q lies on parabols such that PQ is paralel to the x-axis...

i already worked out R is (-2,0) and S is (2,0)

now i need to show area of trapeziumb PQRS is given by:
A = (2-x)(4-x^2)
aaargh!!??? wat!? Area of trapezium = 1/2(a + b)h... but not much help?

then i need to find value of x which gives the maximum value of A... but i think i can work that out if i get this.

pls help, thanx heaps :)

2007-12-02 20:10:29 · 3 answers · asked by Anonymous

(explain the distributive property)

Area: (2x +1) ( x+3) = 2x + 7x + 3
which is: length: 2 + 1 width: + 3

What's the pattern that would work with all of them?other random ones?

(PS: this is grade 8 stuff...)

2007-12-02 20:03:55 · 1 answers · asked by Zobbiezob 3

solve by completing the square
can anyone help me solve this?
thanks

2007-12-02 20:01:06 · 5 answers · asked by ca481 1

i am just really stuck.

Find the standard form of the number
1. 9(cos0 + isin0) (note:its zero not theta)

Perform operation and leave in trigonometric form.
1. [(3/2)(cos pi/6 + isin pi/6)][6(cos pi/4 + i sin pi/4]

2. 9(cos20 + isin20)/5*(cos75 + isin75)

2007-12-02 19:39:35 · 2 answers · asked by Anonymous

Q2.solve the equation tanθ + tan(θ + pi/3) + tan(θ + 2pi/3) = 3

2007-12-02 18:59:53 · 2 answers · asked by ksh_great 1

mean value theorum formula

f*(c) = (f(b)-f(a)) / b-a

2007-12-02 18:58:55 · 1 answers · asked by Jack 1

If sec4x - sec2x = 2, Find cos^2(x) [0 <= x <= π/2]

2007-12-02 18:37:29 · 1 answers · asked by Anonymous

This one seems easy...but I don't think I'm coming up with something solid enough for an official, well-explained proof:

Provide a Counterexample: Every rational number is equal to the product of two irrational numbers

How would you guys go about this seemingly easy counterexample-proof? You obviously can't just say 2*1 = 2 claiming 2 is the product of two rational #'s, right?

2007-12-02 18:28:26 · 3 answers · asked by netsurfer733 2

steps in completeing the square for this equation?

2007-12-02 18:26:02 · 7 answers · asked by chuck g 1

The problem states: Find the volume of the solid bounded by the cylinder x=y^2 and the planes z=0 and z=4-x. HELP ME!!!

2007-12-02 18:03:03 · 2 answers · asked by Anonymous

y=2log base1/2 (x-3)

2007-12-02 17:44:32 · 1 answers · asked by Hello There 1

series: sin (4/n)

2007-12-02 17:41:49 · 1 answers · asked by chimstr 1

(-4^-2x)^-2 e^22x

2007-12-02 17:24:05 · 1 answers · asked by Hello There 1