Mathematics - 13 December 2007

Let f(x)=12-x^2 for x is greater than or equal to 0 and f(x) is greater than or equal to 0.

a. The line tangent to the graph of f at the point (k, f(k) intercepts the x-axis at x=4. What is the value of k?

b. An isosceles triangle whose base is the interval from (0,0) to (c, 0) has its vertex on the graph f. For what value of c does the triangle have maximum area? Justify your answer...

simple explanations would be very very helpful! ;)

2007-12-13 12:20:44 · 2 answers · asked by hello. 1

2007-12-13 12:15:32 · 4 answers · asked by Tay P 1

2007-12-13 11:39:54 · 9 answers · asked by Kim D 1

This is the kind of question my teacher is asking but I do not understand how to do it. I thought that maybe if I heard it phrased differently it might help. I'm looking for a solution to this system of equations.

2007-12-13 11:39:46 · 10 answers · asked by Anonymous

i tried to solve integration by parts and other techniques...but i couldnt solve it... i also dont know if it exists! i want to know how to check its existence and if possiblke the solution of this integral
thank you so much!

2007-12-13 11:34:38 · 5 answers · asked by aydemir i 1

Equation of the line:

(x-1)/3 = (y+3)/1 = (z)/2

Given point (2,3,1)

Find the equation of the plane that has this line and point.
____________________
OK so I got to this point:

In vector form, r(t) = (1,-3,0) + t(5,1,2)

Let t = 0 then (1,-3,0) is in the plane
Let t = 1 then (6,-2,2) is in the plane

So I now have 3 points on the plane. How do I use this to find the equation of the plane?

If I assign "P,Q,R" to these and use:

n = (q-p) x (r-p) = (x,y,z) etc.

Does it matter what point is assigned to P,Q or R? This is what I can't get my head around.

2007-12-13 11:24:14 · 1 answers · asked by Anonymous

2007-12-13 11:20:03 · 11 answers · asked by ??? 2

can some one help me with this

2007-12-13 11:07:36 · 7 answers · asked by Anonymous

this is for my chemistry class. if u didnt get the question its, if you covered washington state in one mole of M&M's how many miles deep would it cover? i figured out that there is 22 M&M's per 25 mL or 22 M&M's per 25 cm^3. I dont know where to go from there and i need to show all my math steps. some helpful conversions he gave me were 1 mole = 6.022 x 10^23. 1 mL = 1 cm^3. and 1 mile = 1.6093 km. and washington state area = 68,182 miles^2 HELP!

2007-12-13 11:06:05 · 4 answers · asked by TeeJay 2

The site will help u see the problem better
Please show work so I can understand it myself better.
http://docs.google.com/Doc?id=dg4zw6jf_5c6ttxchm

2007-12-13 11:02:15 · 9 answers · asked by BBT 1

I have a huge midterm tomorrow and im trying my best to study now but i dont know how to do it?!?

the directions say "solve each system by subsitiuion"
example:

3x-2y=7
x+3y=-5

plz explain how to solve by subsitiutiong for x and y?

2007-12-13 10:59:51 · 11 answers · asked by Anonymous

what is the solution to 2^x=9^x-9

please help!?!?!

2007-12-13 10:57:15 · 1 answers · asked by Ayy Girl! 1

1. y=x-2
y=4x+1

2. 2x+3y=0
x+2y=-1

3. 1/2x+1/3y=5
1/4x+y=10

Dont tell me the answers plz, just tell me the steps and make it easy! Im studying for a huge midterm tomorrow =)

2007-12-13 10:56:37 · 7 answers · asked by Anonymous

she got 26 out of 60

i know shame on her! she is so bad. But what would the percent on her grade be?

I think it is either

43

57

68

or 76

wat do u think!

just write the percent from above that is correct! THANKYOU!

2007-12-13 10:53:52 · 7 answers · asked by Anonymous

At Tio Taco Town a taco contains 2 oz of ground beef and 1 oz of chopped tomatoes. A burrito contains 1 oz. of ground beef and 3 oz. of chopped tomatoes. Near closing time the cook discovers that they only have 22 oz. of ground beef and 36 oz. of chopped tomatoes left. The manager directs the cook to use the available resources to maximize their revenue for the remainder of the shift. If a taco sells for $1.20 and a burrito sells for $1.95, then how many of each should they make to maximize their revenue? (Let x identify the tacos and y the burritos.) Write the system of inequalities that describe this problem and graph the solution set. Show your work for maximizing the revenue

2007-12-13 10:48:56 · 1 answers · asked by Anonymous

solve for x:
cos(2x) = 5sin^2x - cos^2x

been a long time since i did one of these... lol
plz. show each step

2007-12-13 10:43:56 · 1 answers · asked by Anonymous

1. Find all values of k such that the equation: 3x(squared)-2x+k=0 has imaginary roots.

2007-12-13 10:41:50 · 6 answers · asked by Jake 3

Lily bought blue toys for $ 7 each and red toys for $ 5 each. She spent a toal amount of $ 104.
How many of each kind of toys did she buy?

2007-12-13 10:41:28 · 14 answers · asked by I N 2

in the relation c = 50 + 25n, c is the cost in dollars of holding a party in a hall and n is the number of guests. model the situation with a graph & describe which values for C and n do not make sense.

2007-12-13 10:37:23 · 10 answers · asked by Anonymous

for the value of ln(87) would the answer be 4.466 or 4.465?

2007-12-13 10:36:17 · 2 answers · asked by thisisjakethomas 1

2007-12-13 10:33:57 · 10 answers · asked by Kimberly M 1

Does the The Hypotenuse-Leg Congruence Postulate only apply to right triangles, or does it apply to all triangles.

2007-12-13 10:18:03 · 7 answers · asked by Gator Girl 5

Max area of a quadrilateral with a certain perimeter isn't a square most of the time. Is max area of an ellipse with a certain circumference not usually a perfect circle? Is it possible to use a quadratic equation to solve the values of the extreme radii (what's the proper term?) in this case? What about a sphere? Doesn't a perfect sphere have optimal volume? Is area that much different than volume? Why? ¦D This is what my parents put up with!

2007-12-13 10:13:05 · 2 answers · asked by Bennett 3

A right circular cylinder is 188.5 square inches ,if its height is 7 inches,what is it radius?
A = 2pi r h+2pi r^2
188.5=6.28(7)r+6.28r^2
6.28r^2+43.96r-188.5=0
I dont know to how to go from there

A bathroom tub will fill in 15 minutes with both faucets open and the stopper in place. With both faucets closed and the stopper removed,the tub will empty in 20 minutes. How long will it take for the tub to fill if both faucets are open and the stopper is removed?
x=faucets y=stopper ,x+y=15,15-x-y=20
do i set it like this to a system of equations?

An air rescue plane averages 300 miles per hour in still air. It carries enough fuel for 5 hours of flying time. If,upon take off,it encounters a wind of 30 miles per hour and the direction of the airplace is with the wind in one direction and against it in the other,how far can it fly and return safely? Assume that the wind remains constant.
300/(x-30) + 300/(x-30) = 5
[300(x-30)+300(x+30)] /(x-30)(x+30) =5
600x/x^2-900 =5 ?

2007-12-13 10:12:30 · 1 answers · asked by Anonymous

2007-12-13 10:05:05 · 7 answers · asked by Kimberly M 1

can u guys telll me how to do this problem>??
a fair coin is thrown in the air four times. if the coin lands with the head up on the first three tosses,what is the probability that the coin will land with the head up on the fourth toss?

2007-12-13 10:03:51 · 4 answers · asked by Anonymous

I need help because i cant find the importance of slope anywhere.

P.S.
please answer in full sentences....

2007-12-13 09:58:49 · 7 answers · asked by Princezz Icy 2

Emphasis on convex. If not, counterexample please. Thanks.

2007-12-13 09:28:33 · 3 answers · asked by Anonymous

I'm stuck on these few problems. Somebody please help me I've been struggling for an hour now.

I need to find the derivitive:

1. f(x) = (2x^2 + 5)^7
2. f(x) = 1 / 3 square root of 3 - x^3
3. y = x^3 square root of x + 1

this one need you need to find the tangent line equation
4. f(x) = square root of 2x + 1 (4,3)

this one you need to find the acceleration
5. f(x) = square root of x^3 + 1 with x = 2

all answers/help/suggestions are appreciated
Thank You

2007-12-13 09:26:34 · 2 answers · asked by Anonymous

the question reads

find the equation of the tangent to the parabola

y= 5 - x^2 at P(2,1)

Thanks for any help, i really have no idea, do i substitute x = 2 into the equation? so y=1?

then what :s sub in y so it equals 4- x^2 meaning x= +-2? please help

2007-12-13 09:26:14 · 4 answers · asked by AP12 2