Monday
January 26, 2015

Posts by steve


Total # Posts: 28,344

math
since circumference is just a constant multiple of radius, the circumferences are in the same ratio as the radii.
January 9, 2015

Multiplying Polynomials
The order of distribution does not matter, since the associative property guarantees that the order of grouping does not matter, and the commutative property guarantees that the order of multiplication does not matter. You can drag it out by brute force: (t-1)(t+1)(t^2+1) t(t+...
January 9, 2015

Math
well, did you check 24 to see whether it satisfies the conditions?
January 9, 2015

math(5th grade)
Since there are 1440 minutes in a day, that would be 1000000/(25*1440)
January 9, 2015

MATH
Try plugging x=0. Does 7(-2) = 0+14? Do the same for #2. Does -10(-2) = 10-10(-1)?
January 8, 2015

trigonometry
well, you know that sinθ = 3/10
January 8, 2015

Algebra 1
The amount of oil should be twice the amount of lemon juice. y = 2x How much of each ingredient is needed to make 45 ounces of floor wax? x+y = 45
January 8, 2015

Algebra
http://www.wolframalpha.com/input/?i=solve+2x+-+y+%3D+1%2C+x+%2B+2y+%3D+3+
January 8, 2015

6th grade math
I parsed the words as 7 times as long as (x minutes more than a platypus)
January 8, 2015

6th grade math
7(x+10) = 112
January 8, 2015

Algebra 1
12 x^-2 y^4 = 12y^4/x^2 -3xy^-7 = -3x/y^7
January 8, 2015

Algebra 1
for any nonzero number, x^0 = 1 by the way, your brackets are not balanced. Try using [ ] instead of those block graphics symbols. They're right there on your keyboard.
January 8, 2015

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

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