Mathematics - 21 October 2007

Please show some working, I need to know how to do it.

Thanks.

2007-10-21 22:40:48 · 11 answers · asked by Hermione Granger 4

At a given moment, a plane passes directly above a radar station at an altitude of 6 miles. The plane's speed is 500mph. (after drawing a diagram) Suppose that the line through the radar station and the plane makes an angle θ with the horizontal. How fast is θ changing 10 min after the plane passes over the radar station?

2007-10-21 21:46:02 · 2 answers · asked by Anny P 1

Prove that 4|(x-y) is relation of equivalency.

This is gonna be on my exam in 3 hours T_T how do I answer it?

2007-10-21 21:26:33 · 1 answers · asked by Anonymous

Prove that the copying f:R->[1,+∞), f(x)=x²+1 is surjection but not injection.

How T_T, I got exam in 3 hours lol

2007-10-21 21:24:28 · 2 answers · asked by Anonymous

What is the equation of a tangent line if y=(x^2-1)/(x^2+1) and (0,-1)?

I found y' first which i got 4x/(x^2+1)^2
But, when i put 0 into the function, i got the slope of 0.
So, the final equation became y+1=0.
And, it does not seem to me the answer...


Can you plz check and tell me how to reach the right answer?

Thanks :)

2007-10-21 21:13:32 · 3 answers · asked by heyheyhey 2

(Use the identities to find the values of the six trig functions.)
Can someone please explain the process of figuring these kinds of problems out?

1.) x, given cos2x=(-5/12) and pi/2 < x < pi
2.) 2cos^2(67 1/2)-1

2007-10-21 20:58:15 · 1 answers · asked by Anonymous

So I'm still having a bit of trouble understanding the concept of this 'derivative with time' statement.

Take for instance this problem:
circle with radius r. If dr/dt = 4
find dA/dt when r = 3

So...you take pi(r)^2 and take its derivative.
Ok. So the hardest problem with me is understanding what I need to do first. What is it I AM LOOKING for...

or another instance is...
xy = 5
let dy/dt = 1
find dx/dt when x = 1

its all so cumbersome to me still.

2007-10-21 20:48:10 · 3 answers · asked by ret80soft 1

2007-10-21 20:45:08 · 8 answers · asked by nk 1

please help me with this question

determine a particular solution of my'' + cy' + ky = Fcos(wt) of the form Acos(wt - homogeneous solution)

show that the amplitude A is a maximum when w^2 = k/m - 0.5(c/m)^2

thanks so much

2007-10-21 20:43:24 · 1 answers · asked by phil h 2

A guy wire which is 14m long is fastened from the ground to a pole 6.7m above the ground. Find the angle the wire makes with the ground.

2007-10-21 20:33:39 · 3 answers · asked by angilyn c 1

for example; how do i find the derevative of f(3) from a given graph ?

2007-10-21 20:28:37 · 2 answers · asked by Warrior of the Light 3

X=age
Y=income or the equation ( -49x^2+4,606x-52,000)

(^2) means square root or -49x squared (I hope that makes sense)

But if Y= 42080.00

What is X

please help me I'm really stumped.

2007-10-21 20:19:22 · 5 answers · asked by Anonymous

problem 1

the product of two consecutive positive integers is 55 more than their sum. find the integers

problem 2

if 6 is added to the square of a number, the result is 22. find all such numbers.

problem 3

the product of the page numbers on two facing pages of a book is 600. find the page numbers

2007-10-21 20:06:58 · 8 answers · asked by David 1

1. Assume that the radius r of a sphere is expanding at a rate of 14in./min. It's surface area is 4π r^2. Determine the rate at which the surface area is changing with respect to time at t=2min, assuming that r=3 at t=0

2.At a given moment, a plane passes directly above a radar station at an altitude of 6 miles. (after drawing a diagram) Suppose that the line through the radar station and the plane makes an angle θ with the horizontal. How fast is θ changing 10 min after the plane passes over the radar station?

2007-10-21 19:27:55 · 2 answers · asked by Anny P 1

If P(x) = 2x^3 - ax^2 + 10 and P(-2) = 4, find P(3).

What is the value of a?
What is the value of P(3)?

2007-10-21 19:09:50 · 9 answers · asked by Anonymous

2007-10-21 19:09:40 · 6 answers · asked by Anonymous

If the polynomial kx^3 – 15x^2 + 27x – 5k is divisible by x – 2, the value of k is

A) 3
B) 2
C) -3
D) -2

2007-10-21 19:07:58 · 4 answers · asked by Anonymous

Use the remainder theorem to find the remainder when 2x^3 - 1x^2 + 9x - 25 is divided by x + 4.

2007-10-21 19:05:35 · 5 answers · asked by Anonymous

1783814567

2007-10-21 18:57:02 · 19 answers · asked by David 1

Vertical displacement?

2007-10-21 18:48:42 · 2 answers · asked by Lightning 1

x^2-12x= -36

Step By Step Please.

2007-10-21 18:18:15 · 6 answers · asked by Anonymous

2007-10-21 18:14:20 · 3 answers · asked by augusto 1

2007-10-21 18:11:55 · 1 answers · asked by Anonymous

2007-10-21 18:08:19 · 3 answers · asked by Anonymous

help find x

2007-10-21 18:06:50 · 6 answers · asked by Anonymous

plxx help

2007-10-21 18:05:35 · 7 answers · asked by Anonymous

http://i40.photobucket.com/albums/e215/xxs3xp1stolxx/module%20717%20test/Picture13.png

2007-10-21 18:04:31 · 5 answers · asked by Ryan S 1

helpp plzz find x

2007-10-21 18:03:42 · 3 answers · asked by Anonymous

helpp plzzz

2007-10-21 18:02:26 · 2 answers · asked by Anonymous

What is the shortest procedure to follow to determine what 20 is 2% of?

2007-10-21 18:02:08 · 15 answers · asked by selah1925 1