# Posts by Steve

Total # Posts: 52,271

**math**

no way for me to see. However, check your graph against this one: http://www.wolframalpha.com/input/?i=y%5E3+%3D+x-2

**mathematics**

but there are many online articles that show how to do it.

**Mathematics Algebra**

But (x^2 + 2x +4)/(x^2 - 2x - 4) does not always fit into the interval [1/3,3]. If x is very close to 1±?5 then the value is arbitrarily large f(3.2) = -129 plus, you have a typo. I think you mean [9.(3)^2x + 6.(3)^x + 4]/[ 9.(3)^2x - 6.(3)^x +4] using u = 3.3^x That ...

**maths**

huh?

**Mathematics**

"real"ize the denominator by multiplying top and bottom by 1-i sinx. Now you have [tan 2x - i(sinx+cosx)][1 - i sinx]/[(1-i sinx)(1+i sinx)] [tan2x - (sinx+cosx)(sinx) + i(junk)]/(1+sin^2 x) to get zero real part, we need tan2x = sin^2x + sinx cosx any multiple of ? ...

**Math**

For the code, something like count=0 for i=1..2000 with student[i] do { read name,sex,score pct = score*5/2 sub45 = false if pct < 45 then &...

**Math**

If there are x cars and y yellow cars, clearly the new car is yellow, since 1/9 > 1/10 y = x/10 y+1 = (x+1)/9 There are now 81 cars, with 9 yellow.

**trigonometry**

draw the diagram, and it is clear that the distance x is x/100 = tan 50°11'10"

**Math**

c+d = 500 .75c + .50d = 275

**math**

so, you used 304 ft of fence.

**Math, factoring**

Divide by (x^2-x-6) and you get quotient: x^2+(a+1)x+(2a+7) remainder: (8a+24)x + b+6(2a+7) For the remainder to be zero, we need a = -3 b = -6 So, x^4-3x^3-3x^2+11x-6 = (x+2)(x-3)(x^2-2x+1) The other roots are 1,1

**Algebra**

multiply the 2nd equation by 12 and you have 12y = -3x+20 or 3x+12y = 20 so, the two equations are the same.

**Math (Double checking trig identity)**

Nope. my bad. Still you were also wrong (a^2sec?)^2 - (a^2)^2 = a^4 (sec^2?-1) = a^4 tan^2?

**Math (Double checking trig identity)**

not at all. (a^2sec?)^2 - (a^2)^2 = a^4 (sec^4? - 1) = a^4 (sec^2?-1)(sec^2?+1) = a^4 tan^2? (sec^2?+1)

**Cornhole**

if you want names, puntarelli pamela kathryn huckaby

**Math**

No, ?35 is a number like any other, so it has to be included Just as 20+10x is not 30x, 20 + 10?35 is not 30?35 20?35 + 10?35 = 30?35 20+10?35 = 10(2+?35)

**math**

c'mon -- just start plugging in values for n: n=1: 1(1-2)-3 = -4 n=2: 2(2-2)-3 = -3 n=3: 3(3-2)-3 = ... and so on

**Science physics**

work is in Joules 2.0kg * 9.8 m/s^2 * 4.5m = 88.2 kg-m/s^2 = 88.2N-m = 88.2J work = force * distance force = mass * acceleration

**Science physics**

The acceleration is due to gravity g = 9.8 m/s^2

**Math**

correct

**Math**

since the ratio of height:shadow is the same, h/5 = 2/3

**math**

draw the two circles, and a line through their centers. Label the radii, and it should be clear what the two distances are.

**maths**

not sure just what you want to do with this log 5 = 0.699 I guess you can take it from there.

**Math**

(3 3/4)/3 = 1 1/4 Just divide everything by 3

**Algebra**

If the ... indicates some set of repeating digits, the number is rational If not repeating, then it is irrational Either way, it is real

**Math-age problem**

f+g = 60 f+6 = 2(g+6)

**Math**

j = e+5 j-3 + e-3 = 17 now just find 21-j

**Math**

those numbers are all volumes. You need to find pairs of numbers. The sum of their products is the area. Better yet, study the net to see which vertices of the prism are represented; then use what you know about prisms to get the area.

**algebra**

nope. the area will be 1/13^2 as much.

**algebra**

correct

**math**

2/3 as many men, so 3/2 as much time.

**algebra**

no, it will grow by a factor of 4^2 = 16

**Algebra**

just divide term by term, using the distributive property: (4x³ + 10x² + 3a) ÷ 2x² = 4x³÷2x² + 10x²÷2x² + 3a÷2x² = 2x + 5 + 3a÷2x²

**Math**

since east is +x and south is -y (-10,6)+(3,-12) = (-7,-6)

**precal**

No. If you want to find the probability that the marble you drew is blue or green, then that is just the 2/9, since 2 of the 9 marbles are either blue or green. If you mean that after the 1st marble was drawn and not replaced, what is the chance of then drawing a blue or green...

**Calculus**

you can do this as shells or washers. with shells of thickness dy, remember that the volume of a shell is 2?rh. So, draw the region, and ?[0,2] 2?rh dy For discs with holes, of thickness dx, work with ?[1,2] ?(R^2-r^2) dx your job is to examine the region in question and ...

**physics**

see related questions below

**Math**

see related questions below

**Science**

Just add up the displacements and see where you end up. The final displacement is just minus that location. For example, 50m in the direction 30degree west of north is <-50sin30°,50cos30°> = <-25.0,43.3>

**algebra2**

Find the sum of the following series. 14/n-=1 (2n+1)

**Algebra2**

What is the 50th term of the sequence that begins -2,4,10,16? My answer is 292

**math**

correct.

**Functions**

well, (fg)(x) = f(x)*g(x) = (x^2+3)(2x+a) expand that out and equate it to 4x^2-8x+7. The coefficients must all match. That will give you the value of a. Better check for typos, since fg = 2x^2 + ... and there's no way to match that with 4x^2+...

**Physics**

you know that with initial velocity v, s = vt + 1/2 at^2 Now just find s(10)-s(0) and s(20)-s(10) to find a and v.

**Precalculus**

C(x) = 396x + 12320 The price must depend on x if there is a maximum (P is a quadratic), so let's say it is 452-kx. R(x) = x(452-kx) = 452x - kx^2 P(x) = R(x)-C(x) = -kx^2 + 56x - 12330 Without some further data, I cannot say what is the value of k.

**Math**

what is 20% of 50?

**Algebra**

since 33% are girls, and 50% have black hair, some boys have black hair.

**Math**

if we set the center of the base at (0,0) then the parabola is modeled by the equation y = 5/2 - 5/18 x^2 Solve for x when y=2, and the beam has length 2x.

**math**

9!

**maths --plse help me..**

Hmm. I got 6 and 9 Better read the problem again. You got your division backwards: the greater divides the sum.

**maths --plse help me..**

If x < y, then we have (x+y)/(y+1) = 3/2 (y-x)/x = 1/2 Now just solve for x and y

**Science**

well 18g of steam is 1 mole of H2O So, write the balanced equation to see how many moles of Fe will be used. Then get the mass from that.

**math**

the girls walks on a heading, not a bearing. B's bearing from A is 78° If A is at (0,0), then B is at (279,59) If we mark point D due east of A, on the line BC, then D is at (279,0) Now, if angle DAC is ?, then cos? = 279/307 ? = 25° So, A's bearing from C is ...

**math**

use the law of sines. The distance z is z/sin91 = 4/sin44

**MMATH08**

well, since the 10 tiles cover the floor, each must have area 8000/10 = 800m^2 so, the tiles must have side length 20?2 unfortunately, you cannot cover a square floor with 10 square tiles, since 10 is not a perfect square.

**Msth**

just subtract the picture area from the total: (20)(30)-(20-10)(30-10)

**Geometry**

(x,y) -> (x-4,y-8)

**Kaylee - banned**

lim n->? of n ? (5+k(2/n))10(2/n) k=1

**Probability and Statistics**

If you plug some of your numbers in at this web site, I think you'll soon see how things work. http://davidmlane.com/hyperstat/z_table.html

**Trig**

not bad, but why did you subtract? d/dx (x+8)^(1/2) = (1/2)(x+8)^(-1/2) your derivative is good, except for that.

**Math**

to find r, note that a9/a4 = r^5 then use that to find a1

**math**

nope. P(heads) = 1/2 P(n<5) = 4/6 = 2/3 so, P(heads, n<5) = 1/2 * 2/3 = 1/3

**Algebra**

well, I guess you know the answer, then, right?

**Algebra**

none. You need two factors of 24 which differ by 1. Check for typos 1,24 gives 23q 2,12 gives 10q 3,8 gives 5q 4,6 gives 2q

**algebra**

2^(3/4) ----------- = 2^(3/4 - 1/2) = 2^(1/4) 2^(1/2)

**Music**

I guess you have picked the best answer Unlike a piano, whose strings are hit with hammers, and whose volume can vary (piano-forte), a harpsichord's strings are plucked (like a harp's) and always play at the same volume. Listen to some recordings and it's easy to ...

**English**

could is the past tense of can I can swim well. Yesterday I could swim well. Then there are the conditional and perfect uses, but maybe you're not after those.

**physics**

watch the units wavelength(m) = speed(m/s) / frequency(1/s)

**Math (Calculus II) (Partial Fraction Decomposition**

So, you have two polynomials, which are identical. That means all the coefficients on both sides must be the same. That is, x = B(x^2+a^2)(x-a) + C(x+a)(x^2+a^2) + (Dx+E)(x+a)(x-a) = B(x^3-ax^2+a^2x-a^3) + C(x^3+ax^2+a^2x+a^3) + D(x^3-a^2x) + E(x^2-a^2) = (B+C+D)x^3 + (-aB+aC+...

**Math**

They all look ok to me, except #2. Recall that the slope is ?y/?x pick any two pairs and see what you get #3. Note that y increases by 5 for each step. You could not possibly have tried 3x+6 on more than one pair. #5. Again, you clearly only tried n=1.

**Math**

No. There were 10 tosses. 8 of them showed at least one H So, P = 8/10 = 0.8

**Math**

you have it exactly backwards. 0.2 is the probability that NO heads showed.

**Physical Science**

well, 1/16 = 1/2^4 so it takes 4 half-lives

**Math**

16

**Math**

6":18' = 1:36

**math - try again**

fix the typos and post it again.

**math**

each man does 1/(24x) in a day each woman does 1/(32(x+8)) in a day so, 15/(24x) ------------ = 3/1 12/(32(x+8)) yes, x=10

**science**

ever hear of google? http://www.rsc.org/periodic-table/element/8/oxygen

**math**

42

**Math**

well, tan? = 180/215

**Algebra 2**

that's right.

**Algebra 2**

nope. If it has a maximum, then the graph turns back on itself, so it fails the horizontal-line test.

**Geometry**

Since they share a common diagonal BD, they are the same rectangle.

**Algebra 2**

f?g = f(g) = g^2-5g+6 = (x+3)^2-5(x+3)+6 = x^2+x

**Pre Algebra**

7^5 * 7^6 = 7*7*7*7*7 * 7*7*7*7*7*7 = 7^11 all 7's, no 49's

**Pre Algebra**

nope 7^5 * 7^6 = 7^(5+6) = 7^11 Better review the rules of exponents. The base does not change: a^m * a^n = a^(m+n) NOT (a^2)^(m+n)

**Algebra 2**

f(x)-g(x) = (x^2+2x-6)-(3x^2-5x-7) = x^2+2x-6-3x^2+5x+7 = -2x^2+7x+1 watch those minus signs when subtracting!

**Math Graphing**

http://www.wolframalpha.com/input/?i=y%3D+1%2F5x+-+2

**Math**

you are

**Trig help**

A is correct

**calculus review please help!**

for the integral, there are two ways. shells of thickness dx: v = ?[0,2] 2?rh dx where r = 5-x and h=x-x^2/2 v = ?[0,2] 2?(5-x)(x-x^2/2) dx = 16?/3 discs (washers) of thickness dy: v = ?[0,2] ?(R^2-r^2) dy where R=5-y and r=5-?(2y) v = ?[0,2] ?((5-y)^2-(5-?(2y))^2) dy = 16?/3 ...

**maths**

correct

**maths**

If you let u = 4x^2 v = 3-x then you have y = (u/v)^3 y' = 3(u/v)^2 (u/v)' = 3(u/v)^2 ((u'v-uv')/v^2) = 192x^5(6-x) / (3-x)^4

**maths**

All the steps in your work are correct.

**maths - try again**

all that duplicated text is impossible to parse. Try typing it in, rather than copy/pasting. Use t^2 for t squared

**Trig help**

C is correct

**Algebra**

come on. For #5, you have 5x-20y=60 5x-20y=60 They are the same equation. So, any solution to one is also a solution to the other. Try a similar comparison for #6 and just think about what it means.

**math help?!**

correct

**algebra**

15 < 5x

**Science**

correct