Wednesday
October 22, 2014

Posts by Steve


Total # Posts: 25,978

Algebra
Better review your symmetry section. No ideas on any of them?
September 19, 2014

Math
Ah. Finally! a(1-3^8)/(1+3) = -3280 -1640a = -3280 a = 2
September 19, 2014

Math
If the radius of the base is r, then tan(62/2) = r/8
September 19, 2014

math
5P2 = 20
September 19, 2014

Math
√-1 = i √-81 = 9i √-36 = 6i The syntax is garbled.
September 19, 2014

Algebra
(16x^2+1)(x^2+4) = 0 No real roots, but easy-to-find complex roots
September 19, 2014

Algebra
x(x^2+6x+10) = 0 Now use the quadratic formula. There is only 1 real root.
September 19, 2014

Pre-Calculus
of course it's not found - the photo is a file on Cynthia's computer!
September 19, 2014

calculus
well, surely you did some of the steps. What did you find? We can help fill in any missing info.
September 19, 2014

calculus
wolframalpha is your friend: http://www.wolframalpha.com/input/?i=8x^3-2x^4
September 19, 2014

calculus
first: coordinates, not coordination next, a hint: Inflection points occur where f"(x) = 0 and f'(x) ≠ 0
September 19, 2014

Math Precal/Trig
3^7 = 2187, so you have 7(1+2187)/4 = 3829 which is true. But, as I recall, that does not answer the question in the problem as you originally posted it. I suspect that you did not check for that typo.
September 18, 2014

Math (Exponents)
Do you mean 4*10^0 + 7*10^-1 + 2*10^-2 + 8*10^-3? If not, maybe you could splain just what you do want.
September 18, 2014

Math-The chain rule HELP
y = 1/u dy/dx = dy/du * du/dx = -1/u^2 * 6x = -6x/u^2 = -6x/(3x^2+5)^2
September 18, 2014

math
I'd start with the biggest book: 200 = 100+100 200 = 100+50+50 200 = 100+50+10+10+10+10+10 and so on, breaking each possible book down into its parts. Watch out for duplicate entries.
September 18, 2014

trig
Review your basic trig functions. As always, draw a diagram. If the distance is x, tan65° = x/30
September 18, 2014

Algebra2
Since the peak height of 15 was reached at t=3, h(t) = a(t-3)^2 + 15 Since h(0) = 7, a = -8/9, so h(t) = -8/9 (t-3)^2 + 15 Now you can answer the questions
September 18, 2014

Math
Surely you can determine T1 ?? Clearly d = -2b So now just apply your formulas.
September 18, 2014

Math
no diagrams here, but a google on vectors dot product will turn up many discussions and diagrams.
September 18, 2014

Math
t1 = 7/4 d = -3/4 Tn = 7/4 - 3/4 (n-1) ...
September 18, 2014

Math
T2-T1 = 1/20 T3-T2 = 1/12 So, not arithmetic T2/T1 = 5/4 T3/T2 = 4/3 So, not geometric
September 18, 2014

Math
I suspect a typo. Moving right along, S8 = a(1-r^8)/(1-r), so just plug in your values.
September 18, 2014

math
It would certainly be easier to analyze the situations if you had not run them all together into one long sentence. Take the last one. Clearly the net charge is 12(0 + 1 + (-1)) = 12(0) = 0 Surely you have some thoughts on the others. Don't get rattled by all the words; ...
September 18, 2014

Math
Clearly, the nth winner gets 250000 * 0.20^(n-1) This is just a geometric series with a = 250000 r = 1/5 So, just apply your seies formulas
September 18, 2014

Algebra
Assuming a shift to the right, that would be g(x) = (x-2)^2/5 See http://www.wolframalpha.com/input/?i=plot+y+%3Dx^2%2C+y%3D%28x-2%29^2%2F5+for+-3%3C%3Dx%3C%3D5
September 18, 2014

math
I suspect the t was supposed to be a y, making things 3p(x-y) - (x-y) (3p-1)(x-y)
September 18, 2014

algebra
well, that would clearly be 36 + 43e^(-0.058*14)
September 18, 2014

math
That means the exterior angles are 40, so there are 9 sides.
September 18, 2014

Math algebra
probably OOUUUUCCCHHH!!
September 18, 2014

sixth grade math
Odd - you got #1 correct, but missed the other two. 1 5/6 * 2/3 = 11/6 * 2/3 = 22/18 = 11/9 7/8 * 3 1/3 = 7/8 * 10/3 = 70/24 = 35/12 How ever did you arrive at those answers? #2 I could call a typo, but not #3.
September 17, 2014

Chem
wow - can't believe I mangled those digits! But you noticed that on your own, right, Jessica? :-)
September 17, 2014

Chem
the density is evidently 29.3g/(16.7-14.2)ml = 23.9/2.5 = 9.56 g/cm^3 Find that in your table of materials
September 17, 2014

Math
90 boys like soccer, so 150 boys like basketball Assuming those were the only two sports in the survey, that means 240 boys were surveyed. So, 240 girls were surveyed. That means 210 liked soccer and 30 liked basketball.
September 17, 2014

math
Who knows what the names are? But, doing the algebra, 2x^2+3x+1 + x^2+5x+8 = 3x^2+8x+9
September 17, 2014

Math
The LCM is the product if they have no factors in common (relatively prime) Now it should be easy to pick the proper pairs. In fact, since they actually gave you the LCM's, it's just a matter of seeing whether the two numbers multiply to give the indicated LCM!
September 17, 2014

Algebra
Assumiong all the tiles are to be used, find the GCF(45,75,90). That is 15 45 = 3*15 75 = 5*15 90 = 6*15 So, he can make 15 stones, each with 3 red, 5 yellow a
September 17, 2014

science/math
How ever did you get a negative number? I'd assume we are using the same positive acceleration, starting from 50 mph! assuming constant acceleration, then since the velocity changed by 88ft/s in 8 seconds, a = 11 ft/s^2 Now to find v, just recall that v(t) = Vo + at Just ...
September 17, 2014

Algebra! please help
first, complete the squares: x^2+x + y^2-6y = -9 x^2+x+(1/4) + y^2-6y+9 = -9 + 1/4 + 9 (x + 1/2)^2 + (y-3)^2 = 1/4 Now all should be clear. See http://www.wolframalpha.com/input/?i=x^2%2By^2%2Bx-6y%2B9%3D0
September 17, 2014

business in mathematics
After 10 5/12 years, the amount is 9500(1 + .055/4)^(4*10.417) Not sure how the periods are divided into pieces.
September 17, 2014

Algebra 1
what are the numbers moving away from 0? Surely you can figure out how many stairs she has to climb. She has to go down 4, back up to 0, and then up another 4, then back to 0.
September 17, 2014

Algebra
3(a-2) = a 3a-6 = a 2a = 6 a = 3
September 17, 2014

Physics Grade 12
solve for t when the distances are equal: 0 + 1.1t^2 = 12.2t Now recall that since she started from a dead stop, s = 1/2 at^2 v = at
September 17, 2014

Algebra
Assuming the ) means a 0, we want 125 + 0.15x = 75 + 0.40x
September 17, 2014

math
If the rate is constant, then t = md+b Now plug in two pairs of values, say the first two. 8 = 40a + b 6 = 56a + b So, a = -1/8 and b=13 t = -1/8 d + 13 Now check the other two pairs of values to make sure they agree.
September 17, 2014

math help ASAP!!
Do you mean you want to solve the equation? (3x-2)/(x+4) = (18-4x)/(x^2-16) - (3x+2)/(4-x) You need a common denominator. Since x^2-16 = (x-2)(x+2), then assuming x ≠ ±4, (3x-2)(x-4) = (18-4x) + (3x+2)(x+4) Now you can rearrange terms to get -6(4x+3) = 0 so, x = -3/4
September 17, 2014

algebra
I assume you want to find the roots of the function. Since there are no rational roots, wolframalpha is your friend: http://www.wolframalpha.com/input/?i=x^3-9x%2B1
September 17, 2014

Math
x=0, or 7x = 8 If you rearrange terms, 7x^2 - 8x = 0 x(7x-8) = 0
September 17, 2014

Math
You have a slope and a point, so y-3 = -1/3 (x-1) Now all should be clear.
September 17, 2014

Math:Algebra 2
geez, give it a rest, ok?
September 17, 2014

algebra 2
If you are in algebra 2, I guarantee that you were taught this. Remember the point-slope form for a line? It's in your text.
September 17, 2014

M
You have a point and a slope, so use the point-slope form for a a line: y-3 = -2(x-1)
September 17, 2014

math
1/8 the circumference is pi. So, the whole circumference is 8pi Since C = pi*d, d = 8
September 17, 2014

math
John has to make up 50 miles at 10 mi/hr That will take 5 hours.
September 17, 2014

6th grade math
Since a and b are both positive, as long as a < b, a/b < 1 if a > b, a/b > 1 So, just pick some values for each case.
September 17, 2014

math
3/8 ÷ 0.5 = 3/4 2.5 ÷ 18/8 = 2/5 Since 3/4 > 2/5, he has too much milk. He'll get runny pancakes.
September 17, 2014

science/math
assuming constant acceleration, then since the velocity changed by 88ft/s in 8 seconds, a = 11 ft/s^2 Now to find v, just recall that v(t) = Vo + at Just plug in your numbers. Of course, in the real world, acceleration from a standing start is very different from a starting ...
September 17, 2014

math
Since it is a parabola which opens upward, there is no maximum value. g(x) = 2(x + 3/2)^2 - 3/2 so its minimum is -3/2
September 17, 2014

Math
4 -5 7
September 17, 2014

Music
ever heard of google? You will get much more info than you can use in a short paper.
September 17, 2014

Physical Science
since density = mass/volume, volume = mass/density. So, you will displace 3800g / (19 g/cm^3) = 200 cm^3
September 17, 2014

java
you can do one of two things. (1) use a pattern match to place the digits into an array, then print the array elements. (2) convert the number to a string, then loop through the string, printing the 1st character and then removing it, till the string is empty.
September 17, 2014

java
so, the next step will be to accept use input. Check how to do that.
September 17, 2014

Create math equation
If we place Kingston at (0,0) and Queensville at (0,160), then a time t from when Anthony left, the positions will be equal: 45t = 160-40(t - 1/4) t = 2 So, they meet at 2:00+2 = 4:00 pm Or, consider it like this. In the first 15 minutes, Anthony went 45/4 miles. The two cars ...
September 17, 2014

physics
the velocity changes by -20.8 m/s in 3.58s, for an acceleration of (-20.8 m/s) / 3.58s = -5.8 m/s^2
September 17, 2014

algebra
presumably it evaporated or was ionized by the electricity and escaped as H2 and O2 molecules.
September 17, 2014

math
If the breadth is w and the length is x, then we have 2(w+x) = 38 x-3 = 2(w-3) Now just solve for w and x. The area is w*x.
September 17, 2014

algebra
Ix x ml of 10%, then the rest (600-x) is 4%. So, .10(x) + .04(600-x) = .06(600)
September 17, 2014

Math
a = 0.7 a+ar = 2.1 so, 0.7(1+r) = 2.1 1+r = 3 r = 2 So, now you know that S12 = a(1-r^12)/(1-r) Just plug in your values.
September 17, 2014

Math
a + a+d = 15 a+2d + a+3d = 43 collect terms to get 2a+d = 15 2a+5d = 43 That should get you started.
September 17, 2014

math
Enter your polynomials at calc101.com. Click on the long division button.
September 17, 2014

Math (putting the question back up, again)
-5/8 c = 20 c = 20(-8/5) = -32
September 17, 2014

Math
since a = 15 r = 1/3 S4 = a(1-r^4)/(1-r) = 200/9 as you can easily verify with any calculator
September 17, 2014

Math
The first 3 terms form a geometric sequence, but the last is way off scale. As for the sum, why don't you just add up the terms you have been given?
September 17, 2014

Math
t1 = 250000 r = 0.20 Now just plug those into the various formulas you have learned.
September 17, 2014

Algebra help
the slope of L is 3 so, the slope of all perpendiculars to L is -1/3 So, now you have a point and a slope. If that doesn't tell you which form of the equation to use, there's trouble in River City.
September 17, 2014

math
since x = r cosθ r = x/cosθ
September 17, 2014

geometry
No idea. Where is P?
September 17, 2014

Math
Nope. Forgot the 60 degree angle. In that case, recall that cos 60 = 1/2
September 17, 2014

Math
Hint: Think of the ubiquitous 3-4-5 right triangle, scaled up to 6-8-10.
September 17, 2014

n2maths
50^2 + x^2 = (x+10)^2
September 17, 2014

Math
It appears that the two boys are less than 10, since adding up all the ages gives only 83 Granny cannot be less than 83-17=66 66+8+9=83 67+7+9=83 68+6+9=68+7+8=83 69+5+9=69+6+8=83 71+5+7=83 72+4+7=72+3+8=72+2+9=83 73+3+7=83 WE HAVE A WINNER!
September 17, 2014

maths
having what as 5000m?
September 17, 2014

Algebra
correct both times. In general, for a given set of problems, U is the Universe. Any subsets being discussed will always be subsets of U, or things are poorly set up.
September 17, 2014

Algebra
so, use one. wolframalpha.com does a good job
September 17, 2014

math
We have two lines, with slopes (-5-b)/10 and (-3)/(-6-a) If the lines are perpendicular, then (-5-b)/10 * (-3)/(-6-a) = -1 (b+5) = 10/3 (a+6) b = 5/3 (2a+9)
September 17, 2014

Math
We have a=7 d=12 So, when does Tn exceed 1000? Tn = 7+12(n-1) = 12n-5 12n-5 < 1000 12n < 1005 n < 83.75 So, the first 83 terms are less than 1000 Similarly for 2000
September 16, 2014

Math
clearly, a = 28 r = 1/6 So, S = a/(1-r) = 28/(5/6) = 33.6
September 16, 2014

Math
since x has an unspecified value, there is no way to round it. So, I assume you want to solve the equation, and round the answer to two decimals. 2x^4+3x-4 = 0 There are only two real roots, x = -1.43 or 0.90 The graph is at http://www.wolframalpha.com/input/?i=2x^4%2B3x-4 Or...
September 16, 2014

math
16/10 is the same as 1.6
September 16, 2014

math
probably because you have learned by heart some simple results, like sums totaling 10, or 5, etc. The mechanics never change, so if some are easier, it just means that you have learned some patterns that you can recognize.
September 16, 2014

math
The language is very confusing in its use of present and past tenses. When is "now"? The end of the year? If girls joined the band, how come there are now fewer students than at the beginning? I cannot believe the question was posed as you state. If so, the problem ...
September 16, 2014

trigo
First, vessels travel on headings, not bearings. 200 @ 245° = (-181.262,-84.524) 50 @ 320° = (-32.134,38.302) add them up to get (-213.396,-46.222) = 218 @ 258°
September 16, 2014

Algebra
correct.
September 16, 2014

Calculus
f(a) = 3a^2-2a f(a+h) = 3(a+h)^2 - 2(a+h) = 3a^2 + 6ah + 3h^2 - 2a - 2h f(a+h)-f(a) = 6ah + 3h^2 + 2h So, (f(a+h)-f(a))/h = 6a + 3h + 2 So, with various values of h, f(a+1) = 6a+3+2 f(a+0.1) = 6a + 0.3 + 2 = 6a + 2.03 and so on. Nothing difficult, just algebra I.
September 16, 2014

Math
That's a lot of work. Just think about it a bit. You start with 1 gram. 3 days later the amount left is 0.1 gram If the half life is k days, then (1/2)^3k = 1/10 3k = log(.1)/log(.5) = 3.32 So, k = 1.11 R(t) = (1/2)^(1.11t) But, since we like things base e for our ...
September 16, 2014

Math
just solve for x in the equation −0.01x2 + 130x − 180,000 = 174900
September 16, 2014

math
The expression factors as (3x-1)(x+2) However, there are lots of other ways to divide things up. For example, if x=3, the area is 8*5 = 40, but those are not the only two ways to get two numbers which multiply to 40.
September 16, 2014

math help
Just plug in the value: (4x+8)(x+2)(2x+4) / 2((4x+8)(x+2)+(4x+8)(2x+4)+(x+2)(2x+4)) = 8(x+2)^3 / 28(x+2)^2 = 2(x+2)/7
September 16, 2014

Math
steps to what?
September 16, 2014

math
The answer is r^2-5 + 5/(r^2-2) See the details when you enter your polynomials at calc101.com. Click on the long division button.
September 16, 2014

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