# Posts by steve

Total # Posts: 50,526

Algebra
compare Bh to 1/3 Bh in each case for volume similarly for area

Math
just plug your points into x^2/a^2 + y^2/b^2 = 1 then solve for 1/a^2 and 1/b^2

Math
The direction numbers for the last two points make the line from t=0..1 x = 2-t y = 0-t z = -1+4t So, backing up to z=3, -1+4t = -3 t = -1/2 a = x(-1/2) = 5/2 b = y(-1/2) = 1/2

Calculus - Integrating
The problem is that you did not have du in your integrals. You lacked the extra 2x dx in your integrands. u = x^2+1 du = 2x dx x = ?(u-1) So you have ?x/?(x^2+1) x dx = 1/2 ??(u-1)/u du which isn't really much better Try using a trig substitution: x = tan? x^2+1 = tan^2...

math
s = t^3-9t^2+3t+1 v = 3t^2-18t+3 = 3(t^2-6t+1) so, solve for t when v=-24 a = 6t-18 then plug in that t to find v and a. what is your problem with minus signs (-) ? over- and under-score really are ugly! x^2 cosy - siny = 0 Surely you can plug in the point to verify it fits! ...

MATHEMATICS

Science
2Mg + O2 -> 2MgO now convert to moles for amounts needed

College algebra
If the half-life is k years, then after t years, (1/2)^(t/k) remains. Thus, to find k, solve (1/2)^(400/k) = 0.7 600 = 3/2 * 400, or 1.5 half-lives. So, the amount remaining after 600 megayears is (1/2)^(3/2 * 400/k) = (1/2)^(400/k)^(3/2) = 0.7^(3/2) = ?

English
the literary device of foreshadowing is used in which of the following excerpts? They're spoiled and we're spoiled Those screams -- they sound familiar I have a feeling it'll be Africa again before then They're not old enough to do that alone, I explained My ...

English
thank you

English
my second choice was number 2

English
Which of the following is a way that imagery can be used? to present facts during debates to inspire audiences during speeches to entertain readers with a play on words to impress readers with facts and evidence My answer is the third one

English
Then it would have to be subjective

English
when doing research writing it is important to avoid being? timely, detailed, objectives, subjective My answer is detailed

Mathematics for social science
20P3 10C4

English

English
Absurdism is the attempt to show the ________ of the human condition. silliness seriousness uniqueness hopelessness my answer is the last one

English
thank you

English
Scientists report (1) that creatures living in the deep sea are in danger of starving to death. The underlined part of sentence 1 is what kind of clause? adverbial clause adjectival clause noun clause Independent clause My answer is independent because if you remove the word ...

math
75% = 3/4 He gave 42 to Joe

math
I'm assuming your asking how many did Keith get? 56*3/4=42 Leon gave to Joe 42*2/7=12 Joe gave to Keith 3/4= 75% 2/7=28.6%

Calculus
The weight of oil in the tank is w = (20*25? m^3) * (820 kg/m^3) * 9.8 = 4018000?N The center of gravity of the oil is 20m from the top of the tank, so the work required to empty the oil is 4018000? * 20 = 80360000? J Or, using calculus, the weight of oil in a thin layer of ...

Physics
Scroll down some here, and all is explained. http://www.insula.com.au/physics/1279/L14.html

Math Functions Functions
to shift right by h, replace x with (x-h) to shift up by k, replace y with (y-k) Thus, y-3 = (x-2)^2 shifts y=x^2 right 2 and up 3. Reflecting across an axis changes the sign of the other variable. Thus -y=x^2 reflects y=x^2 across the x-axis. Now see what you can do.

math- factoring
If two polynomials are identical, all the coefficients must match. So, a = 2 b = -13 c = 21

Math
(5?3,5)+(0,-4) = (5?3,1)

Math
in standard form, you have x^2+4x - 4(y^2-6y) = 28 x^2+4x+4 - 4(y^2-6y+9) = 28+4-4*9 (x+2)^2 - 4(y-3)^2 = -4 (y-3)^2 - (x+2)^2/4 = 1 Now use that with your standard properties of hyperbolas. check with this: http://www.wolframalpha.com/input/?i=hyperbola+(y-3)%5E2+-+(x%2B2)%...

Math
|p| = ?(42^2+35^2) = 7?(6^2+5^2) tan? = 35/42 = 5/6

Math
.075x + .12(5000-x) = 819

Physics
(10cos37,-10sin37)+(-14,0) = (-6,-6)

look at the differences. 1st: -0.2, -0.6, -1.0, -1.2, ... 2nd: -0.4, -0.4, -0.4, ... so, look for a linear relationship between y and x^2: y = 3-5x^2 fits pretty well, at least at first

Math
cos(2x) = 1 - 2sin^2(x) now just use your numbers.

Math
A. 32.65+(38.4-25) = ? B. 32.65+(x-25) = 50.15

numerical methods in finance
Just plug in your formula. If you have trouble with that, youtube has several videos showing examples.

math
small = 47/22 - 1/2 large = small + 40/11 small = 36/22 large = 116/22

Geometry
it is easy to show that ?NOD ? ?MOB check out vertical angles and recall that the diagonals bisect each other.

Math
y = 550 * 0.948^t

Math
recall that the sum of two adjacent angles is 180, so ...

Math 120
(3990-1890)/3990

Maths
clearly, P(3k) Q(2k)

Math
review the cot(x) function: h cot30 - h cot45 = 1

Math
tan? = 9/3 and try proofreading what you type. It's a mess.

calculus
what, you can't just plug in the 6 values of t? Even after the explicit example given? No calculus needed here, just basic algebra!

Maths
gotta be (d) since the point spread does not change

Math
o = 3s o+3 = 2+2(s+3) Olivia is 15

Math
construct a 60° angle AOB Bisect it. Measure out the hypotenuse and mark A. Construct the perpendicular to OB.

College Algebra
P(t) = 15.1*2.06^t

Algebra
This is just an extension of finding the line passing through two points. Plug in the points for Ax+By+Cz = 0 and solve for A,B,C.

Physics
F = ma constant velocity means a=0

Calculus
Huh, you can't figure the dimensions of s square of area A? The maximum area for a given perimeter is a square. The minimum perimeter for a given rectangular area is a square. So, the length and width would both be ?A But, since you seem to be taking calculus, look at the ...

Calculus
a square

algebra
hint: 24 = 5*5 - 1

Linear algebra
Clearly you did not continue reading to the section where it showed how to find Q1 and Q2.

Algebra

maths period help
recall that the period of cos(kx) is 2?/k

Math
draw a diagram and review the tan(x) function

Math
Draw a diagram. It will be clear that if the pole has height p and the building has height h, then h/145 = tan34 (h-p)/145 = tan26

Math
draw a diagram and check on the cot(x) function.

ALGEBRA
I can't figure out your function. Usually these things are quadratics, so try writing it using x^2 for "x squared" and "*" for multiplication, since "x" is the variable name.

calculs
The distance from (3,-6,4) to a point (x,y,z) on the paraboloid is d^2 = (x-3)^2 + (y+6)^2 + (z-4)^2 = (x-3)^2 + (y+6)^2 + (x^2+y^2-4)^2 the partials of z are zero at (1,-2) and d^2 = 21 For centroids, just plug in to the formula. Should not be hard.

Math
If the three classes have debts of x,y,z then we know that y = x+458 z = x+1165 x+y+z = 6543 Now just crank it out.

calculs

calculs
A: The curves intersect at (-3,6) and (1,2) So, consider the volume as a set of nested cylinders of thickness dx. Then v = ?[-3,1] 2?rh dx where r=3-x and h=(-x^2-3x-6)-(3-x) v = ?[-3,1] 2?(3-x)((-x^2-3x-6)-(3-x)) dx = 2??[-3,1] (3-x)(-x^2-2x+3) dx = 256?/3

Maths
.42 If you still don't like the answer, take a look at what you asked, and think on how we could possibly know ... Then ask again, giving the information necessary.

math
Why repeat everything? 24+3r >= 100

Pre calc
It took 9 days to shrink to 1/4 its size. 40/640 = 1/16 = 1/4 * 1/4 So, it will take another 9 days to do that again.

Trigonometry
If you fix your typo: 2tan 23° / (1 - tan^2 23°) and recall your double-angle formula for tan(x) you will see what you need to do.

Trigonometry
#5 since trig functions are periodic, they have infinitely many solutions. #6 So the function and its inverse are 1-to-1. All the trig functions fail the horizontal-line test for inverses unless the domain is restricted, just like something simple like y=x^2.

science
5*2 N-m = 10 J work = force * distance

Math
a = 1.2b b = 1.25c a = c+58 Time to stop avoiding algebra! 1.2(1.25c) = c+58 1.5c = c+58 0.5c = 58 c = 116 Clara spent 116 Amy spent 174 Betty spent 174/1.2 = 145 so, add them all up.

Maths
The Lemma says that for any pair, a,b we can find q,r such that a = bq+r The above equation is just a ? r (mod 5) There is no unique value of a which will determine r.

Maths
0.42

9th Math
Draw one of the triangles formed by two radii. If the side length is s, then s/2 = 5 sin20° Find s, and p=9s

science
yes - the thrust is determined by the volume of liquid displaced.

maths
Assuming you meant (p+(pq^2)^1/3+(p^2q)^1/3)/p that term is 1 + (q/p)^1/3 + (q/p)^2/3 If you let u = (q/p)^1/3 then you just have (1+u+u^2)-q(1-u) But q = pu^3 Not sure just where you want to go with this. Your typos make things a bit murky.

science
h(t) = 20t - 5t^2 max height is at t=2 h(2) = 40-20 = 20

math
2+24 = 26

Maths
20/0.75 = ?

Maths Trig
Draw a diagram. You will see that sin? = 18/30 Extra credit: How wide a ship can pass through the opening?

math
Since all of 15,20,30 divide 300, the cube is 20x15x10 blocks in size. So, it can be cut into 3000 blocks. Or, using the idea above, divide the volume of the cube by the volume of a block: 300^3 / (30x20x15) = 27000000/9000 = 3000

Algebra
C appears to be a quadratic. As with any quadratic ax^2+bx+c the vertex lies at x = -b/2a So, find C(x) at that value.

Algebra
A^-1 exists if |A| is not zero. Here, |A| = 21-20 = 1 so, A has an inverse.

English
Which of the following lines from a&p illustrates updikes use of conflict A. the whole store was like a pinball and I didn't know which one they'd come out of. B. you could see the, when Queenie's white shoulders dawned on then, kind of move, or hop, or hiccup but ...

algebra
Peter's age now: x Paul's age now: y x-y years ago, Peter was y years old. x = 2(y-(x-y)) x+y = 56 Peter is 32 Paul is 24 8 years ago, Peter was 24 and Paul was 12.

Algebra
1/y - 1/(y+5) = 1/10 y = 5 check: 1/5 - 1/10 = 1/10

Math
Draw a diagram. You will see that h cot40° = (h+7) cot60°

Basic Math
If 13 is the slant height of a triangular face, then the area of the pyramid is just the base plus four triangles: 11*11 + 4*(11*13/2) = 407 I keep having trouble guessing what you mean by "side" especially of a cone.

calculus
lim x?? {(5x ? 4)/(5x + 3)}^5x lim x?? {(1 - 7/(5x+3))}^5x Let u=5x lim u?? {(1 - 7/u)}^u I assume you can now see that this is e^-7

calculus
using L'Hospital's rule we have lim x?0 (e^x ? e^?x ? 2x)/(x ? sin(x)) lim x?0 (e^x + e^?x ? 2)/(1 ? cosx) still 0/0, so do it again: lim x?0 (e^x - e^?x)/sinx and again: lim x?0 (e^x + e^?x)/cosx ? (1+1)/1 = 2

Math - Trigonometry
of course there is. I assume by "opposite" you mean at the same height on the opposite slanting face. If the base has side 2s, and the pyramid has height h, then If the point P is at height y, then it is at a distance x from the central axis of the pyramid. Using ...

Linear Algebra
#4 No, ?200 = 14.14

Algebra
well, father will be 36 in 4 years, so ...

Math - Geometry!!!
Well, it is certainly not a triangle. If you reorder the points a bit, it should be clear:    (3,3),(7,3) (1,1),(5,1)

Math
(2/3)(3/4)-(1/6) = 1/3

Math
Square ABCD has side length 60. An ellipse E is circumscribed about the square and there is a point P on the ellipse such that PC = PD =50. What is the area of E? I got to the part with the point (30, 30). Now what next?

Help Polynomial
Start off with what you know. Substituting x = a,b you have Ra+S = P(a) Rb+S = P(b) Now just solve for R and S.

Math, Induction
test for n=1 3.7^2+1 = 14.69 BZZZZTT! But thanks for playing. I suspect a typo in your presentation.

Math - Trigonometry
I like 'em. People use decimals because of calculators. When I see °'" I run to my trig tables and do some interpolation!

Science
The resistance of each piece is still 25 ohms. Now, if a single 25-ohm wire had been cut into five pieces, then each piece would have had a 5-ohm resistance. That is not what we have here.

Science
think about it. The current has 5 different paths it can follow, so the resistance is 1/5 as great. So, 5 ohms 1/R = 1/25 + 1/25 + 1/25 + 1/25 + 1/25 = 5/25 = 1/5 So, R=5 Why would you think it is 1? Time to study some more.

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