Friday

March 6, 2015

March 6, 2015

Total # Posts: 29,433

**MATH**

If there are x married men (or women) y single men z single women, we want 2x/(2x+y+z) (x+z)/2 = z (x+y)/6 = y x = z x = 5y so, z = 5y 2x/(2x+y+z) = 2*5y/(2*5y+y+5y) = 10/16 = 62.5% Check: If 1 single man 5 single women 5 married couples there were 16 people in the room. 10 ...
*January 8, 2015*

**Ap calc**

You should also know that y = tanh(x) y' = sech^2(x) = [2/(e^x+e^-x)]^2
*January 8, 2015*

**Advanced Algebra**

Is the ball punted straight up? If so, then h = 1+22t-4.9t^2 So, just solve for t when h<=5. If the ball was kicked at an angle, things get a bit harder, as the equation is then h = 1 + 22sinθ t - 4.9t^2
*January 8, 2015*

**Math**

since the fill rate is volume/time, and is constant, then just solve (40^2 * 5)/50 = (36^2 * 4)/x
*January 8, 2015*

**math**

check your other post for the answer.
*January 8, 2015*

**MATH**

15-.75x = 13-.50x Now just find x 15 - 3/4 x = 13 - 1/2 x 60-3x = 52-2x 8 = x After 8 games, Julia has 15-8*.75 = 15-6 = $9.00 Kevin has 13-8*.50 = 13-4 = $9.00
*January 8, 2015*

**math**

k = 2a k-7 + a-7 = 31 so, 2a-7 + a-7 = 31 3a-14 = 31 3a = 45 a = 15 So, Amy is 15 and Ke is 30 7 years ago, 8+23 = 31
*January 8, 2015*

**algebra**

google is your friend. So is any used book store. This site is not for long instruction, but for homework help.
*January 8, 2015*

**Algebra 1a**

First off, there are no "these two points." Second, the solution to the system of inequalities is a whole region of the plane, not just a point. If we are dealing with equations, then the point where the lines meet is (-126/11, 21/11) The shaded region in the plot ...
*January 8, 2015*

**Geometry**

since 24/16 = 3/2, the perimeter will be 3/2 as big. All the sides are 3/2 as big.
*January 8, 2015*

**Math**

S = 9/(1-r) If r>=0, you can see that 9/1=9 would be the smallest possible sum, if r=0. That is, if the sequence is 9 0 0 0 0 0 ...... Any other value for r will produce nonzero terms, and therefore a larger sum. You can investigate what happens when r < 0.
*January 8, 2015*

**Math**

These are just your basic trig functions. Review them and the first three are trivial. I'll do #4. sin^2x / 1+cosx (1-cos^2x)/(1+cosx) (1-cosx)(1+cosx)/(1+cosx) 1-cosx If indeed your teacher assigned these problems with no prior introduction to the trig functions, then don...
*January 8, 2015*

**math**

x+19 >= 8.2
*January 8, 2015*

**Useless Science Question**

the question is "what is missing?" It doesn't want an answer to what it should be.
*January 8, 2015*

**Useless Science Question**

the units km/hr, m/s, cm/ms ?what?
*January 8, 2015*

**Pre-Calc/Trig**

eq #1 says that 7y^2=5x^2-20x+3, so plug that into eq #2 and you have 5x^2+3(5x^2-20x+3) = 209 20x^2-60x-200 = 0 x^2-3x-10 = 0 (x-5)(x+2) = 0 And I think you can take it from there, no?
*January 8, 2015*

**science**

I'd get the answer by looking it up somewhere. Unless you have some data about amounts and times, there's no way to figure it out yourself. Can you see what a useless question you have posted? Sheesh! And, I think you have missed your deadline...
*January 8, 2015*

**Math**

x^2-3x-4 = (x-4)(x+1) So, you have x/[(x-4)(x+1)] - 4/(x+1) (x - 4(x-4))/[(x-4)(x+1)] (16-3x)/[(x-4)(x+1)] As usual, you cannot divide by zero, so any values of x that make a denominator zero are excluded. Now show us what you got on the others you posted. As it says, show ...
*January 8, 2015*

**Math**

what the heck are tries toom points ? If this is the old trisection problem, then you know that AQ = 2 PQ, so 7x+6 = 2(3x+5) 7x+6 = 6x+10 x = 4 PQ = 17 Now, AB = 3 PQ = 51
*January 8, 2015*

**math**

-1 < 2x/3 + 1 <= 4 Add 1 to get 0 < 2x/3 <= 5 times 3/5 to get 0 < x <= 3 Looks like x is any of 1,2,3
*January 8, 2015*

**calculus - ps**

Sorry - I forgot to include the factor of a on the right side. It will just multiply the final answer, since it's a constant.
*January 8, 2015*

**calculus**

(x-y)(x^2+y^2) = 2axy In polar coordinates, that is r(cosθ-sinθ)(r^2) = 2ar^2 sinθ cosθ r(cosθ-sinθ) = asin2θ r = asin2θ/(cosθ-sinθ) The loop is the area enclosed as θ goes from π/2 to π, so the area is a = &#...
*January 8, 2015*

**MNHS_HELP**

63^3+63^2+63+1 = (63^4-1)/(63-1) = 63^4-1 So, your number is 63^4-1+1 = 63^4 = 3^8 * 7^4 So, the prime factors are 3 and 7 I'll leave it to you to determine how many factors there are in all
*January 8, 2015*

**Math**

Remember that r is the ratio between successive terms. As for the infinite sum, remember that S = a/(1-r), so 7/(1-r) = 4
*January 8, 2015*

**maths**

gotta know radius or angle, or something else. s = rθ a = π/2 r^2 θ = π/2 rs
*January 8, 2015*

**maths**

h/60 = tan 30°
*January 8, 2015*

**math**

T5 = T2 + 3d, so d = (22-7)/3 = 5 The sequence is 2 7 12 27 22 Technically, the above is an arithmetic sequence. If you truly wanted an arithmetic series, then you'd have to use the sums S2 = 2/2(2a+d) = 7 S5 = 5/2(2a+4d) = 22 a = 16/5 and d = 3/5 The sequence is 16/5 19/5...
*January 8, 2015*

**College Algebra**

well, just answer the question. Find x when y=9. -0.146x+11.074 > 9 -0.146x > -2.074 x < 14.2 So, 1980-1994 Do the other in like wise.
*January 8, 2015*

**Algebra**

1/(x-5) = 7/2x 1(2x) = 7(x-5) 2x = 7x-35 5x = 35 x = 7 Whenever you have fractions, make sure that your answer does not make a denominator zero. In this case, things were ok. x=5 and x=0 would be excluded as solutions, since you cannot divide by zero.
*January 8, 2015*

**Algebra**

correct.
*January 8, 2015*

**Algebra**

t/8t + 16/8t = 17/8t t+16 = 17 t=1 That's the only solution I can see.
*January 8, 2015*

**Math**

well, it will triple 4 times. So, what is 3^4 * 1mm ?
*January 7, 2015*

**math**

I believe the angles should sum to 90°
*January 7, 2015*

**Math**

#2. I believe we are discussing a square, not any rectangle. x = -6 y = 6
*January 7, 2015*

**AP Calc. AB**

so, now you just want to find where -2*3x^2 e^x^3 = -6 x^2 e^x^3 = 1 I think a graphical solution will be easiest.
*January 7, 2015*

**Math**

k^-3 = 1/k^3 So, you want 1/k^3 = 1/256 k^3 = 256 Now, 256 = 2^8, so k = 2^(8/3) = 2^2 * 2^(2/3) = 4∛4 Hmmm. we got trouble. (a) and (b) are out. 4^-3 = 1/4^3 = 1/64 64^-3 = 1/64^3 = 1/4096 I think that 1/256 is a mistake. Or, the -3 is a mistake. 16^-2 = 1/16^2 = 1/256 ...
*January 7, 2015*

**Math**

wow - use run-on sentences much? If the base is x by y and the height is z, just break the area into rectangles lateral area: 2(xz+yz) total area: 2(xz+yz+xy) Now just plug in your numbers. You didn't say which was which.
*January 7, 2015*

**math**

2/3 = 16/24 3/4 = 18/24 So, what do you think is in between them?
*January 7, 2015*

**Math**

5^13 = 5^6 * 5^7 The powers on the right can be any two numbers which add up to 13.
*January 7, 2015*

**physics**

how long does it take the dart to fall 0.32 m? 4.9t^2 = 0.32 with that t, find the distance is 13.5t
*January 7, 2015*

**Algebra 1**

2(x+y) = 100 But, y = 3x+2, so 2(x+3x+2) = 100 ...
*January 7, 2015*

**math**

20*2πr = 45*60 must be a wind turbine.
*January 7, 2015*

**math**

6C2 = (6*5)/(1*2) = 15
*January 7, 2015*

**Algebra**

remember that log x^n = n*log x So, log(4)(3x + 4)^5 = 15 5log(4)(3x + 4) = 15 log(4)(3x + 4) = 3 3x+4 = 4^3 = 64 3x = 60 x = 20 Expanding (3x+4)^5 would not help, because then you just have a polynomial, but the log of a sum cannot be simplified. log(x^2+3) is not log x^2 + ...
*January 7, 2015*

**Math**

Assuming you mean (1+2x)/(x+4) = 3/(x-1) (1+2x)(x-1) = 3(x+4) 2x^2 - x - 1 = 3x + 12 2x^2 - 4x - 13 = 0 Now it's just a regular old quadratic equation to solve. Note that right from the beginning you have to exclude -4 and 1 from the domain.
*January 7, 2015*

**Math**

2x^2-2 = 2(x-1)(x+1) 2x^2-8x+6 = 2(x-1)(x-3) Now rewrite your fractions with the factors, put all over a common denominator of 2(x-1)(x+1)(x-3) and simplify the numerator. Probably something will cancel out. Non-permissible values are those that make any denominator zero.
*January 7, 2015*

**Math**

#1 I haven't followed the argument through yet, but I think if you play around with 0 < a < 1 (x+1)^a <= (x+1)^1 x^a + ax^(a-1) + ... + ax + 1 <= x+1 things will work out.
*January 7, 2015*

**MATHS**

well, (42)^2 - (38)^2 - (17)^2 = 31 so that should get you started...
*January 7, 2015*

**maths**

well, you have a = π/2 r^2 θ So, plug in a and r to find θ, and then you know that the arc length s = rθ Or, do it at one fell swoop: s = r(2a/(πr^2)) = 2a/πr
*January 7, 2015*

**Maths trigonometry**

secAcotB-secA-2cotB+2=0 secA(cotB-1) + 2(cotB-1) = 0 (secA+2)(cotB-1) = 0 Now it should be clear what the angles are.
*January 7, 2015*

**Math**

yes, as long as x≠1 (1-x) = -(x-1), so you have -x^2(x-1) ------------- (2x-3)(x-1) and the x-1 factors cancel.
*January 7, 2015*

**Algebra**

well, does it work in both equations x-3y = -5-3*2 = -11 ≠ 1 So, I'd say a resounding NO.
*January 7, 2015*

**Algebra**

the 2nd equation says that y = 2x-4 So, substitute that into the 1st to get 2x + 4(2x-4) = -2 Surely you can solve that, and then find y ...
*January 7, 2015*

**Math**

p' = 1-p that should get you started.
*January 6, 2015*

**algebra**

11x + 11(x+1) > 100 11(x+1) + 11(x+2) < 200 22x > 89 22x < 167 4.04 < x < 7.59 So, the numbers can be 55 66 77 66 77 88 77 88 99
*January 6, 2015*

**math**

I can't find the integers until you clarify what the difference between five times the greater even integer is 14 means
*January 6, 2015*

**Math**

To find the x-intercept, set y=0 and you have 1.8x = 6.3 x = 3.50 Now do similarly to find the y-intercept. Set x=0.
*January 6, 2015*

**math**

The wall is 174 x 66 x 6 inches. That is 29 x 16.5 x 3 bricks. If we have to round up (no partial bricks reused), then that is 29 x 17 x 3 = 1479 bricks.
*January 6, 2015*

**PHYSICS NEED HELP ASAP**

157-75 = 82 km/hr = 22.78 m/s -22.78m/s ----------- = 3.25 s -7.00 m/s^2 so, now just use your motion formula. 157 km/hr = 43.61 m/s, so s = Vo t + 1/2 at^2 and plug in your numbers.
*January 6, 2015*

**math**

You know that the sets of numbers have to range from 2 to 8 to satisfy the max and range requirements. Half of them must be greater than 5 and half must be less than 5. 6 must occur most frequently. So, starting with a small set, we could start out with 2 5 6 6 8 Since there ...
*January 6, 2015*

**hvac**

Assuming a constant voltage, then since E = IR is constant, (1.2)(240) = I(540) Now it's easy to find the new current.
*January 6, 2015*

**Finite Math**

just solve for r in 24000(1+r)^5 = 34616
*January 6, 2015*

**math-algebra**

yes, (3a^5)^2 = 9a^10 6x^2 * 12x^3 = 72x^5 Why did you assume x=5?
*January 6, 2015*

**Math**

well, 10x^2+3x-1 = (5x-1)(2x+1) now the rest is a cinch.
*January 6, 2015*

**math**

If there are x quarts of 2% fat, then the rest (40-x) is 7%. So, just add up the fat content: .02x + .07(40-x) = .05(40) x = 16 Looks like (B) to me. You can actually get the right answer without even doing the math. C and D are clearly out, since the total is not 40 quarts. ...
*January 6, 2015*

**Bosaso**

You can do all kinds of fun Z table stuff at http://davidmlane.com/hyperstat/z_table.html
*January 6, 2015*

**math**

9.5 * 11.00 * 1.07 = ?
*January 6, 2015*

**physics**

Let the two forces be ax and by a^2+b^2 = 25 a^2 + b^2 - 2abcos120° = 37 or a^2+b^2+ab = 37 ab=12 So, it looks like the two forces are 3kN and 4kN
*January 6, 2015*

**maths**

I have a bit of trouble deciphering just what you mean, but my best guesses are 4x + 4x + 2-3y+8 = 8x-3y+10 or 12x or 3(2-3y+8) = 30-9y
*January 6, 2015*

**physics**

conserve momentum: 70*(+5) + 5(-20) = (70+5)v v = +10/3
*January 6, 2015*

**math**

If the bottles numbered w,x,y,z respectively, then we have w+x+y+z = 20840 w = 8120 y = 3960 x = y+2000 Now you can solve to find z.
*January 6, 2015*

**math**

GCF(30,48,72) = 6
*January 6, 2015*

**math**

clearly a painter can paint 1/180 of the job in one day. So, 20 painters can paint 20/180 = 1/9 of the job in a day, making the total 9 days. So, it takes 3 days less. Not also that you could reason that if the number of painters is increased by a factor of 5/4, the time taken...
*January 5, 2015*

**Physics**

since c=18, r = 18/2pi Now look at the fountain sideways. The height h can be found by noting that h/r = tan 55.0° Now just figure h.
*January 5, 2015*

**math**

n = 5*35
*January 5, 2015*

**geometry**

The height is 24tan63° + 24tan38°
*January 5, 2015*

**math**

hey - let's learn the distributive property! 6x6 = (5+1)x6 = 5x6 + 1x6 = 30+6 = 36
*January 5, 2015*

**math**

1+2 = 4-1
*January 5, 2015*

**Math**

well, we have aq = 2(pq), so 7x+6 = 2(3x+5) x = 4 ab = 3(pq) = 3(17) = 51
*January 5, 2015*

**Math**

((x + 2)/5) + ((3x - 4)/10) 2(x + 2)/10 + (3x - 4)/10 (2x+4 + 3x-4)/10 5x/10 x/2 I think you forgot to divide by 10 at the end.
*January 5, 2015*

**Math problem solving**

Clearly the maximum area is when four of the sides of the octagon are along the sides of the square. Thus, that leaves us with four unused triangles, each of side s where s/√2 + s + s/√2 = 750 s = 750/(1+√2) The area of each such triangle is thus (750/(1+&#...
*January 5, 2015*

**Math**

Looks like 12 and 15 to me
*January 5, 2015*

**exponents ,factor,fraction**

is there supposed to be a "c" in the expression? Whatever, just plug in the numbers for the letters and evaluate. Show your work in case of trouble.
*January 5, 2015*

**distance**

I get |2+9/4|/√(1/16 + 1) = (17/4)/√(17/4) = √17/2 To see how, take a look at http://en.wikipedia.org/wiki/Distance_between_two_straight_lines
*January 5, 2015*

**Math**

20+8y-9y-21 = -y-1 Now check the others: 2(10+4y-7y-19) = 2(-3y-9) = -6y-18 Nope and so on Hint: try grouping for #D
*January 5, 2015*

**algebra 1**

well, did you try actually checking the possibilities? 21 > 16+2 yes 21 < 16+5 no and so on for the others
*January 5, 2015*

**Mathematics**

ln u^n = n * ln u ln u*v = ln u + ln v ln u/v = ln u - ln v Better review the basic properties of logs.
*January 5, 2015*

**algebra**

I assume you mean +17/22 though "opposite" is a vague term with no precise mathematical meaning.
*January 5, 2015*

**Solid mensuration**

since a = 1/2 r^2 θ, just plug in π/3 and 6, and calculate a = (1/2)(36)(π/3) = 6π
*January 5, 2015*

**math, solving Oblique Δ**

A+B+C=180°, so C=115° Now use law of sines: b/sin49° = c/sin115° = 10/sin16° #2: sin88°/8 = sinB/7, so B = 61° or 109° But, since A=88°, B cannot be 109°, so there's no ambiguous case here. Now you know A and B, so you can find C and...
*January 5, 2015*

**algebra**

You just want to find x/y. I'll do #3, as the first two are trivial. xa+xb = yc+yd x(a+b) = y(c+d) x/y = (c+d)/(a+b)
*January 5, 2015*

**algebra**

the amount of gold in each alloy is the %age times the total mass: .10x + .30y
*January 5, 2015*

**math**

You have the answer. Did you guess it, or calculate it? You know that even numbers are multiples of 2 (2k), so odd numbers are of the form 2k+1. So, you want 2k+1 + 2k+3 + 2k+5 - (2k+3) = 50 4k+6 = 50 4k = 44 k = 11 So, the numbers are 23,25,27
*January 5, 2015*

**Mathematics**

just figure the difference between the outside and inside volumes: V = πr^2 h, so you want π(10.4+0.8)^2(25) - π(10.4^2)(25) = 25π(11.2^2-10.4^2) = 432π
*January 4, 2015*

**Calculus**

If the balloon is at height h, then the distance z from the child to the balloon is z^2 = h^2 + 40^2 When h=30, z=50 So, now we want dz/dt when h=30 2z dz/dt = 2h dh/dt Just plug in z=50 and h=30 and dh/dt=5 and solve for dz/dt
*January 4, 2015*

**Algebra I**

as with all word problems, translate the words to symbols. Then you have equations which can be solved. If there are a adult and c child tickets, you have two sets of facts: the number of tickets and their cost. c + a = 64 1.00c + 2.50a = 109.00 Now you can use your math ...
*January 4, 2015*

**computer science check**

The above comment refers to the actual syntax of the program. During the design, however, it is quite common to write the calls first, as that sets up the program flow of logic. Then the function definitions fill in the details.
*January 4, 2015*

**computer science check**

The languages vary, but in the strictest case, functions must be defined before they can be called, so A is my choice.
*January 4, 2015*

**physics**

they absorb most light except in the orange wavelengths, which they reflect back to our eyes. Now, as to the physical/chemical properties of the "carrot" molecules which cause that behavior, I have no clue.
*January 4, 2015*

**Pre-Calc**

well, geez. when t=8, y=33+30cos(0) = 63 Isn't that what you wanted, the max height at t=8?
*January 4, 2015*

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