Wednesday
April 16, 2014

Posts by steve


Total # Posts: 21,705

math
(11000-8690)/11000 * 100 = 21%

precal
I hope one of the choices was y=5

Math
for any value of x, f(x) = -5x+1 So, wherever you see an x, substitute a -2 and you have f(-2) = -5(-2)+1 = 10+1 = 11

Algebra 1
#1 nope. If you subtract -3 from 9, you don't get 6. 4 x 10^12 #2 yes #3 (4y^6/x^3)^2 = 16y^12/x^6 #4 yes

Calculus
And you arrive there by using partial fractions: 1/(x^2-1)^2 = 1/4 (1/(x+1) + 1/(x+1)^2 - 1/(x-1) + 1/(x-1)^2)

Calculus
x^3/(x+1)^2 = x - 2 + 3/(x+1) - 1/(x+1)^2 Now it's a piece of cake. ... Right?

Calculus
That pesky y' gets in the way. The solution is really y = c1 e^x + c2 - 1/2 (sinx - cosx)

Math
since p/d is constant, 30/80 = p/50

Algebra 1
#1 nope. If you subtract -3 from 9, you don't get 6. 4 x 10^12 #2 yes #3 where did b come from? I suspect you mixed up problems. (4y^6/x^3)^2 = 16y^12/x^6

precal
the domain is all reals. e^z is never zero, so we don't have to watch out for that. Unless your typo conceals the fact that you means f(x) = 2 + 1/(e^(x/3)-5) In which case we cannot have e^(x/3)-5 = 0 e^(x/3) = 5 x/3 = ln 5 x = 3 ln 5 = ln 125 For the inverse, swap variab...

Algebra
Your post so far: 0 words. Whattaya got? In your own words, that is.

phisecs
final displacement is 8 km in 3 hrs, so v = 8/3 km/hr North His speed, on the other hand, is non-directional, so it is just distance covered = 18/3 = 6 km/hr

Grammar
"are" is correct. FWIW, I thought the first post was ok. The "there" isn't really necessary. The structure is simply Trapdoors into the dungeons are at the end of some passages.

Geometry - incomplete
what do you mean "A=14" ? A is a point or and angle.

Geometry
learn to recognize common triangles. 5-12-13 is one of them. Now everything should be easy. Come back if not. Might as well show your work while you're at it . . .

Geometry
assuming the figure is a rectangular prism, you know that volume = length x width x height. Just plug in the data given.

math
just divide what you have: (3/10)km / (7/12)L = (3/10 * 12/7) km/L = 36/7 km/L

Math
on the other hand, rate usually involves a time period, as in km per hour ft per second So, I think I'd have to change my answer to ratio, the ratio of points to games.

Math
rate The "per" usually indicates a rate, as in miles per gallon population per square mile

Calculus
y = cx + x ln^2(x)

Intermediate Algebra
If the 1,2,3 pointers are in amounts of x,y,z, then x+2y+3z = 95 x+y+z = 54 y = x+16 (x,y,z) = (17,33,4)

algebra
well, what is y-0=2000?

Math
Hmmm. The integers are . . . -12 -11 -10 -9 -8 -7 -6 . . . What do you think?

Math
recognize the 3-4-5 triangle scaled up to 6-8-10?

algebra
if you add some spaces, it should be clear: 2x/5 - 9 + 9 OK?

math
It occurs to me that I may have misinterpreted the unseen diagram. If the 70° angle is on the face of the pyramid, then we have h/(b/2) = tan 52° and the slant height s is in the other triangle, rather than just h, so √((b/2)^2+h^2)/√(b^2/2 + h^2) = sin 70&...

math
looking perpendicular to one face of the pyramid (base a square of side b, and height h), h/(b/2) = tan 52° looking up the edge, h/√((b^2/2 + h^2) = sin 70° Clean things up a bit, and you can solve for b and h

algebra
it's the equation of a line in the x-y plane.

Algebra
3x + 4(3-x) = 25

physics
Suppose two children push horizontally, but in exactly opposite directions, on a third child in a wagon. The first child exerts a force of 75.0 N, the second a force of 95.0 N, friction is 12.0 N, and the mass of the third child plus wagon is 21.0 kg. (c) Calculate the acceler...

2nd Math
If she's learning about them, there must be some examples in her text. Study them and if you get in trouble, post one here for help.

Math
add 2/24 to both sides and you have y = -3/24 = -1/8

Math
3/8 = 7/(x+1) 3(x+1) = 7(8) 3x+3 = 56 3x = 53 x = 53/3

bcc
t=9 h = t + b/3 b = h+t knowing t=9, we have h = 9 + b/3 b = h+9 so, h = 9 + (h+9)/3 h = 9 + h/3 + 3 2h/3 = 12 h = 18 b = 27 t = 9 add 'em up for the total weight

Math
since a/bc is constant, 100/(5*25) = a/(12*60)

Math
just figure their slopes. If the slopes are the same, L1║L2. If their product is -1, then L1┴L2. Otherwise, neither.

Math
since xy is a constant, (24)(6) = 15x

Math
just set up the expressions and solve for m miles (10m .1-mile segments): 2.50 + .20(10m) = 3.25 + .15(10m)

Algebra
(d) no two pairs have the same 1st element.

Algebra
ummm. try them out till you find one that fits. That's what I would have to do...

Math
Recall that |n| = n if n >= 0 |n| = -n if n < 0 So, you have four cases to consider: (6x-2) >= 0 (6x-2) < 0 (3x+1) >= 0 (3x+1) < 0 In pairing up the conditions, some may be incompatible. On the other hand, while the expressions may be positive or negative, th...

Calculus
(-1/(x+2) + 1/2)/x = ((-2+x+2)/(2(x+2)))/x = (x/(2(x+2)))/x = 1/(2(x+2)) = 1/4 as x->0 No tricks here; just a little algebra

Math - incomplete
You don't say how wide the side windows are. Nor the width of the opening in the wall. One or the other will be needed to figure the other base of the trapezoid. If the entire wall is devoted to the bay window, then you need to say whether it is on the short side or the lo...

Science
I agree

advanced functions
Remember your algebra I? Subtract 980 from both sides. You want to have f(x) = 0 to solve for x.

Math
75 + 15x >= 140

Algebra
y varies directly as x^3

calculus
A simpler solution uses the fact that the area of an ellipse is πab Here, a=4 and b=5, so the area of the ellipse is 20π. Since all the triangles have the same height (6), the volume is (1/2)(6)(20π) = 60π

calculus - pi indeed
Ah, yes. I forgot the √ in my integral. I also get 60π I thought it strange that there was no π, but I was in a hurry at the time. Score one more for Damon.

calculus
using symmetry, we can see that since the area of each triangle is 1/2 yz v = 2∫[0,5] yz dx where y = 4√(1-x^2/25) and z=6 v = 48/5∫[0,5] ∫(25-x^2) dx = 800

Pre-Algebra
as illustrated and explained here: http://math.about.com/od/formulas/ss/surfaceareavol_5.htm the area is just the square area of the base plus the areas of the four triangles forming the sides. And, as we all know, the area of a triangle is 1/2 base * height (the slant height ...

Science
I agree

Homework help plz( Steve or Reiny)
No Yes Express all as powers of 10^-8 and you get 13.5 18.0 6.00 2.50 Arrange those in order Order powers of 10, then the digits, if the powers are equal: 10^-2 10^-1 1.3*10^3 2.0*10^3

Physical Science
start at (0,0) after (a): (4,0) after (b): (4,-6) after (c): (0,-6) after (d): (0,0) final position is back at the starting point.

math
find x such that tan(x) = 0.06

algebra - aargh
come on -- ask a question that makes sense. Can you not see that you give no idea what it is you want?

algebra
try proofreading your post before submitting it. I will have to guess associative, based on the garbled text

Java - nope
I have an idea - why don't you write one, see whether it runs, and if not, post a real question.

Math (pre calculus)
As written, you have ax + b/cx + d = 2 acx^2 + (d-2)cx + b = 0 x = [c(2-d)±√((c(d-2))^2-4abc)]/2ac I assume you meant (ax+b)/(cx+d)=2 2(ax+b) = (cx+d) 2ax + 2b = cx + d (2a-c)x = d-2b x = (d-2b)/(2a-c)

pre cal
If you mean (a+1)/b = (a-1)/b + (b+1)/a ((a+1)-(a-1))/b = (b+1)/a 2/b = (b+1)/a 2a = (b+1)/b a = (b+1)/(2b)

Finance
suppressing all the irrelevant zeros, we have 42(1+r/12)^(12*23) = 100 (1+r/12)^276 = 2.3809 1+r/12 = 1.003148 r = 3.777%

math12A TRIG pleas help
since the hypotenuse is 200, the legs are 200 sin 43.2° and 200 cos 43.2° calculate those and just add up the 3 sides.

Math 3rd grade - eh?
It can, given the proper tools. is there more to this question?

math
2000 * (1+.13/2)^(2*10) * (1+.08/4)^(4*10) = 15,560.70

Math
.03x + .05(25000-x) = 1100

Algebra
let there b x par-3, y par-4, z par-5 holes. Then x+y+z = 18 3x+4y+5z = 66 y = 2z Now just solve for x,y,z

Algebra 2
n ∑ (10-3i) = -28 i=1 You know that n ∑ 10 = 10n i=1 You know that n ∑ i = n(n+1)/2 i=1 so n ∑ -3i = -3n(n+1)/2 i=1 Now just add them up: 10n - 3n(n+1)/2 = -28 n = 8

logarithms
3^x = 6 x log3 = log6 x = log6/log3 or, by definition, x = log36

Math
6^2 + 24^2 < 25^2 so it will do

math
if the base has side s and the prism has height h, then the painted area (the top and three sides) is 1/4 s^2 √3 + 3sh

Math
vertical angles are always equal adjacent angles are supplementary

Advanced Math
I'd have to say 10(1/4) + 0(1/2) + 5(1/4) = 3.75

calculus
a = ∫[0,1] 2π y ds where ds = √(1+(y')^2) a = 2π∫[0,1] (x^3+3)√(1+9x^4) dx The ∫(x^3)√(1+9x^4) dx part is easy, but the ∫3√(1+9x^4) dx cannot be done with elementary functions.

algebra
2x-3y-3=0 x = 3(y+1)/2 y = 2/3 x - 1 y = 2/3 (x-3/2)

Pre-Calc
length = 50-2w area = w(50-2w) max area at w=25/2

Science
you can find your answer at the following site http://yougrowgirl.com/glossary/

math
5 is not greater than 8,000, so the real question must be greater than 8,000 what?

Science
you can find your answer at the following site http://www.ehow.com/info_8371471_accessory-parts-flower.html

calculas
First step is usually to find the derivative: f = 7xe^(-7.5x) f' = 7e^(-7.5x) + 7xe^(-7.5x)(-7.5) = 7e^(-7.5x) (1-7.5x) since e^(ax) is never zero, we just need to see when (1-7.5x) = 0. I think you can take it from there. The graph is at http://www.wolframalpha.com/input/...

Calculus Help
F = 9/5 C + 32 As we all know, C >= -273.15

calculas
oops. wrong problem. y = 60000/x p = 2x+4y = 2x + 4(60000/x) dp/dx=0 when x=200√3 and y=100√3 p = 800√3 But, as usual, the length is equally divided among lengths and widths.

calculas
as usual, divide the fencing equally among lengths and widths. So, I'll go ahead and predict that the solution will be 7500 x 15000

Math
an ice cream cone-shaped thingy among others

math 1 question --- pls check my work!
since you say nothing about the dimensions of the cylinder, it's hard to choose, innit? If the radius and height are both 12, then D is correct. Or if r*h = 144

4th garde math
Penny has p cookies Jenny has 2p cookies Winnie has 2p+4 cookies So, add them up: p + 2p + 2p+4 = 44

algebra
since 45 = 5*9 what is 5*3?

PLS HELP ME WITH ONE MATH QUESTION!!???
consider the triangles the bases, since they are parallel. Then there are 3 lateral edges and faces, which join the bases.

Calc 2
or, by this time you have probably seen L'Hospital's Rule, so limit √x sin(1/x) if u = 1/x, then we have limit sin(u)/√u = limit cos(u)/(1/2√u) = limit 2√u cos(u) as u->0 = 0

Chemistry
3 moles of H2 produce 2 moles of NH3 3.65*10^-4 g of H2 is 3.621*10^-4 moles H2 That will produce 2.414*10^-4 moles of NH3 2.414*10^-4 * 6.023*10^23 = 1.454*20^20 molecules NH3

Trig
E arctan(49/48) S = E 45°35' S = 135°45' Actually, that is the pilot's heading. It also happens to be the bearing of the airport from the plane.

algebra
you wrote |-4b-8|+|-1=b2|+2b3 I shall endeavor to unravel the typos. If I get it wrong, fix it and follow the logic provided to arrive at the correct solution. |-4b-8| + |-1-b^2| + 2b^3 |-4(-2)-8| + |-1-(-2)^2| + 2(-2)^3 |8-8| + |-1-4| + 2(-8) 0 + 5 - 16 -11

algebra
most of your graphing needs can be found at http://rechneronline.de/function-graphs/ Just enter the functions (up to three) For this one, you probably should change the y-range to -10 to 10

math
35000(1.08)^10

Physics 2
An antenna is connected to a car battery. Will the antenna emit electromagnetic radiation? Why or why not? Explain

maths
the last sentence says 21 <= n <= 99 one digit prime and n=3k+1 means we have something in 25,34,43,52,58,61,67,70,76,79,85,91,94 reverse digits is prime means we have 34,67,91 sum of digits is prime means 34,67 four factors leaves 34, which has factors 1,2,17,34

Calculus
∫ -dt/√(1+2t-t^2) = ∫ -dt/√(2-(1+t)^2) Now recall that ∫ du/√(a^2-u^2) = arcsin(u/a) So, that gives us -arcsin (1+t)/√2 = -arcsin (x+2)/((x+1)√2) I don't see where the √3 comes from, nor the arcsinh. I suspect a typo in...

Math
since these events are independent of each other, you just multiply their probabilities. Since there are 3 hearts out of 15 cards, P(heart) = 3/15 = 1/5 P(heart,heart) = 1/5 * 1/5 = 1/25

Math
since sqrt4 is just 2, you have (-8±2*2)/2 = (-8±4)/2 = -4±2

Math
1/3 m + 15

Math
x+y = 12 x-y = 24 2x = 36 x = 18 y = -6 I figure you can pick the larger one.

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