Monday
February 20, 2017

Posts by steve

Total # Posts: 48,672

Algebra
don't forget your Algebra I. h(t) is just a quadratic, and the vertex (maximum height) is at t = -b/2a = 26/32 = 13/16 Now use that to find h(13/16)
February 13, 2017

Maths
Sn = n/2 (A1+An) = 8/2 (6+46)
February 13, 2017

Trigonometry
4rpm = 16 in/min, so 1 rev = 4in 2?r = 4, so r = 2/? for the 8" wheel, the ratio of radii is 8/(2/?) = 4? So, if its radius is 4? as big, its speed is 1/(4?) as fast, or 16/(4?) = 4/? in/min It makes 1/(4?) * 4 = 1/? rpm Your unknown radius is ok, but I don't see how ...
February 13, 2017

Calculus for Business Administration and social s
?(432x^12) = ?(8*27*2 x^12) = 6x^4 ?2
February 13, 2017

Maths
Let the length AM=1. Let C be the midpoint of AM. Draw the line CO. It has radius 1/2 + r. Draw the line MO. It has length 1-r. So, in the right triangle CMO, 1/2^2 + (1-r)^2 = (1/2 + r)^2
February 13, 2017

math
you know that the length is between 19.5 and 20.5 meters the width is between 2.5 and 3.5 meters So, use the largest and smallest values to get the range of perimeters.
February 13, 2017

Math 115
45-4.5t
February 13, 2017

Math 115
I'll do one: C(t) = 45 - (45-27)/4 * 4 - (27-18)/2 * (t-6) = 27 - 9/2 (t-6) = 54 - 9/2 t if 6 < t <= 8 This should give a clue to the other parts...
February 13, 2017

math
average value is integral divided by the interval width.
February 13, 2017

math
I'm guessing you meant ?[4,7] (1+x^2) sinx dx or something. Try reposting with better notation. You can also use my notation above at wolframalpha.com to evaluate integrals.
February 13, 2017

math
not quite clear on your notation, but the distance is the integral of the velocity over the interval.
February 13, 2017

Physics
recall that KE = 1/2 mv^2 PE = mgh Now just plug in your numbers.
February 12, 2017

Statistics
visit this site for Z table stuff: http://davidmlane.com/hyperstat/z_table.html
February 12, 2017

Trigonometry
Good work, but I interpret the wheel size as the diameter. If so, same steps apply, just adjusted for the smaller radius.
February 12, 2017

Stats
you can play around with Z table stuff here: http://davidmlane.com/hyperstat/z_table.html For this problem, you find that 99.7% of the area lies less than 2.748 ? above the mean.
February 12, 2017

Algebra
12r+11s = 228 6r+5s = 108 ...
February 12, 2017

Math
I don't know what you mean by it "didn't work." It just shows that the expression is never positive. (x-2)^2 is a square, so it is always positive So, -(x-2)^2 is never positive. Trying to plug a formula into a request for a proof will never work. The logic ...
February 12, 2017

Math
= -(x^2-4x+4) = -(x-2)^2
February 12, 2017

Algebra
x+y = 900 .05x + .08y = 64.50
February 12, 2017

Algebra
12a+2c = 122 7a+8c = 160 ...
February 12, 2017

science
Ca comprises 2/3 of the 1.28g CaCO3, or 0.853g So, assuming that all of the calcium is contained in the CaCO3, the 0.853g is 31.37% of the 2.72g pill
February 12, 2017

college math
The maximum area occurs when the fencing is divided equally among lengths and widths. For all 4 sides fenced, that is a square. In this case, with the length parallel to the wall, we have length=500/2 = 250 and width = 500/2/2 = 125 so the area is 250*125 = 31,250 This is ...
February 12, 2017

math
try typing the equations yourself; copy/paste does not do well here. You can copy and paste the ? symbol as you go.
February 12, 2017

math
.13x + .09(x+700) = 239 x = 800 as above.
February 12, 2017

Geometry
Draw diagonals AC and DF. The hexagon is now divided into a parallelogram (rectangle?) and two congruent triangles. AC and DF can be found using the law of cosines, since all the interior angles are 120 degrees.
February 12, 2017

math
what you mean is 2 <= x <= 5 This is just a parabola, with vertex at (2,-1). So, clearly, f(2) = -1 is the minimum value. The axis of symmetry is at x = 2, so f(5) will be the max on the interval [2,5], since it is away from the axis.
February 12, 2017

Algebra
So, why not use a 1? |3y+4|-1 = 0 |3y+4| = 1 3y+4 = 1 3y = -3 y = -1 3y+4 = -1 3y = -5 y = -5/3
February 12, 2017

algorithm
for i=1 to 5 prompt for marks read marks[i] next i
February 12, 2017

number base help plz
1234 = 4^2 + 2*4 + 3 = 2*8 + 8 + 3 = 338
February 12, 2017

College calculus
x = u/(1 + u^3) y = u^2/(1 + u^3) dy/dx = dy/du / dx/du dy/du = u(2-u^3)/(1+u^3)^2 dx/du = (1-2u^3)/(1+u^3)^2 dy/dx = u(2-u^3)/(1-2u^3)
February 12, 2017

Mathematics of finance 1
see related questions below
February 12, 2017

maths
bricks: 180*6*50 * 8 = ? tank: Assuming a square base, v = 150*150*40/1000 L
February 12, 2017

math
the principal (not principle) can be found by solving P*1.04^2 - P = 1632 P(1.04^2-1) = 1632 ...
February 12, 2017

math
If x is at 3%, then the rest (12000-x) is at 5%. So, add up the interest: .03x + .05(12000-x) = 460
February 12, 2017

math
If he traveled x miles by bus, then he went 1900-x by plane. Since time = distance/speed, x/60 + (1900-x)/700 = 5
February 12, 2017

basic calculus
w = width 54/w = height The page area is thus a = (w+1)(54/w + 2) Assuming you want minimum page area, da/dw = 0 at w = 3?3
February 11, 2017

Math
The amount of bacteria after n seconds is A = Q*3^(n/15)
February 11, 2017

*physics*
1W = 1J/s = 1N-m/s so, 3500 kg * 9.8N/kg * 9.50m /(9000N-m/s) = 36.2 s
February 11, 2017

Physics
PV=kT, so PV/T is constant You want T such that 2*25/(T+273) = 1*20/(120+273)
February 11, 2017

Math
Try using the minus (-) sign for subtraction, not the underscore (_)! Anyway, you got them almost all wrong: -4+6+9y = 2+9y (since 6-4=2) 20a+7+3 = 20a+10 -5k+9-2+9k = 4k+7 OK 17+2.9h+3 = 20+2.9h -4(3+d)+7d-d = -12-4d+7d-d = -12+2d 8+5(j-5)+3j-1 = 8+5j-25+3j-1 = 8j-18 9(b-3)+4...
February 11, 2017

math
1.065x = 160000 x = 150234.74
February 11, 2017

math
125-(7+9-5) = ?
February 11, 2017

math
I don't know, but since y = x+2, x-2 = (5/6)x+1 Now solve for x, and then y=x+2
February 11, 2017

MATH TEST(tipps)
As longs as you're studying, work on your English: I have a math test in a week; plz give me some tips so I can pass it
February 11, 2017

maths
well, if u = x-y v(u) = u/3
February 11, 2017

maths
A*(x,y)T = (4,4)T (x,y)T = A-1(4,4)T
February 11, 2017

Algebra 2
Not sure I get this step, since ^ is right-associative: 3^(1/2)^x = a^(1/6) 3^3^x = a As written, that means 3^(3^x) I was thinking (3^(1/2))^x = a^(1/6) 3^(x/2) = a^(1/6) 3^(3x) = a 3^3 = a^(1/x) = a^b 1/x = b x = 1/b
February 11, 2017

Math
(203/2.2)/40 * 10 = 23.07 mg
February 11, 2017

Calculus 2
actually, it appears I was right after all...
February 10, 2017

Calculus 2
I may have misspoken. Take a look here for a discussion of the topic. faculty.atu.edu/mfinan/2243/business65.pdf
February 10, 2017

Calculus 2
Money at 2% grows like e^0.02t The amount deposited at time t gets to grow for (9-t) years. Seems to me like the account balance after 9 years is thus ?[0,9] R(t) * e^(.02(9-t)) dt
February 10, 2017

math
(1 1/2)(1/2) = 3/4 So, the new dimensions are 3/4 the original ones. You can do the math now...
February 10, 2017

Algebra
see related questions below.
February 10, 2017

Algebra
Not sure just what you're after. If the sums in the ratio 3:1 are just the first five terms, then a^2(1-r^10)/(1-r^2) ------------------------- = 3 a(1-r^5)/(1-r) ar = 4/3 a = 4/(3r), so plug that in, and (4/(3r))^2(1-r^10)/(1-r^2) ------------------------- = 3 4/(3r)(1-r^...
February 10, 2017

Math
cutting out the fat (!) (16^2/6^2) * 630 / 8 = 560
February 10, 2017

Math
3/5 x + 100 = 2/3 x x is in mL Now just solve for x. And that's liters, not literature!
February 10, 2017

Mathematics
the volume of the orange is ? * 12^2 * 6.75 = 972? cm^3 Now use what you know about the volume of a sphere to get the radius of the orange, and thus its surface area.
February 10, 2017

Math College freshman
(-100-20)/(40-20) = -6 so, the slope is -6, and we start with h = -6x But -6(20) = -120, and h(20) = 20. So h(x) = -6x + 140 You can check to make sure this fits the other points as well.
February 10, 2017

College Algebra
.15*5 = 0.75 So, T = .15p+0
February 10, 2017

Math 115
Clearly, W = 5x+5 The answer key must have an error.
February 10, 2017

Math
correct on both
February 9, 2017

Cmax
Any decent calculator has a button for ex somewhere. Probably an alternate function for ln.
February 9, 2017

Science
the filament has electrical resistance. When electricity passes through it, it generates heat -- so much heat that the wire glows.
February 9, 2017

math
Nope. The rate of growth is the slope of the line. Study (D) to see why it is the choice.
February 9, 2017

math
(b^2)^0 = 1 = b^8 So, b = 1 or -1 Just use the rules of exponents as usual. Negative values are still just numbers! p(p^-7q^3)^-2q^-3 = p * (p^-7 q^3)^-2 * q^-3 = p * p^14 q^-6 * q^-3 = p^15 q^-9
February 9, 2017

Math
.49p = 72.89
February 9, 2017

math
try writing them as 26x - 12y = 4 9x - 12y = -30 Now just subtract the equations and the y's will vanish.
February 9, 2017

English
Bob, I am a 70-year-old grandfather trying to help his grandson. Yes, I have read the book. After going and checking the difference between limited and omniscient I would say that the right answer should be 1st person omniscient.
February 9, 2017

English
The great gatsby is written in which point of view. 1st person limited 1st person omniscient 3rd person limited My answer is c
February 9, 2017

Calculus prince@18
h(x) = ?[2,x^2] arctan(t) dt from the 2nd Fundamental Theorem of calculus (and the chain rule), h'(x) = arctan(x^2) * 2x if F(t) = ?arctan(t), then h(x) = F(x^2) - F(2) now the chain rule gives the result, and d/dx F(2) = 0 If we had had h(x) = ?[lnx,x^2] arctan(t) dt then...
February 9, 2017

math
1 3/2 is bogus. Mixed numbers do not generally have a fractional part greater than 1. Anyway, 3^2 = 9 1 3/2 = 5/2 = 2.5 and now it should be clear. Do the others by putting them all over a common denominator (8), and then just sort the numerators.
February 9, 2017

PHYSICS
the fine article in wikipedia on "trajectory" explains this and more. The formula for the range is R = v^2/g sin(2?)
February 9, 2017

Math
the slope is -3/5 So, now you have a point and a slope. The line is y-4 = -3/5 (x+6) They don't call it the "point-slope" form for nothing!
February 9, 2017

Algebra II
neither one is. (a+b)^2 = a^2 + 2ab + b^2 neither one of these has a middle term. No idea what the "original monomial" could be. x? 4? 2?
February 9, 2017

math
why ever would you subtract radius from height? The volume of towels is the volume of the whole package, minus the volume of the inner cylinder. Recall that the volume of a cylinder is v = ?r^2 h. So, the volume of the towels is ?*12^2*18 - ?*5^2*18 = 2142? cm^3
February 9, 2017

Math/Chemistry
Have you forgotten your Algebra I? Ao/A = kt Ao = Akt
February 9, 2017

Geometric problem solving
first off, the circumference is measured in meters, not m^2. If C = 2?^2, then 2?r = 2?^2 r = ? So, A = ?r^2 = ?^3 m^2 If you meant to find the circumference when the area is 2?^2 m^2, ?r^2 = 2?^2 r^2 = 2? r = ?2? C = 2?r = 2??2? = (2?)^(3/2) Actually, I think you just messed ...
February 9, 2017

math
convert all to have the same power of 10, then it will be clear. For example, 2.3 * 10^5 = 230 * 10^3
February 9, 2017

Math
1/6 * 1/6 * 1/6
February 9, 2017

Precalculus
<k,2>•<3,5> = 0 3k+10 = 0 k = -10/3 gotta watch those ± signs!
February 9, 2017

Math
13/14 = 0.92857 = 92.857% The remainder from 13/14 is 13! Try some other number, say 72/13 = 5 7/13 = 5 R 7 The remainder is always less than the divisor, so 13/14 = 0 13/14 = 0 R 13
February 8, 2017

Finance
Which type of debt is the least attractive for a consumer? Unsecured debt Secured debt Mortgage debt Lease debt My answer is unsecured debt
February 8, 2017

Math
2(4+6) * $4.84
February 8, 2017

Math
no, that would make the answer 8m=102 ...
February 8, 2017

math
Note that you have two right triangles, with a common angle. So, they are similar, with all angles equal.
February 8, 2017

Algebra
well the function f is usually written in the form f(x) = 2x-2 so D looks like the choice intended. But saying Volume(radius) = 67 is a bit strange, since it implies that no matter which value "radius" has, the Volume remains constant at 67. If the value of Volume is...
February 8, 2017

math
I see that this time you omitted the instructions to make a Venn diagram. Did you do that, or are you just waiting for the answers? It appears that you must have meant 6 study only biology since you already said that 60 study biology. I think there is still something missing ...
February 8, 2017

Math
You might have check my solution given earlier before reposting the problem: http://www.jiskha.com/display.cgi?id=1486538658
February 8, 2017

examples of pop singers
Do you have some inappropriate ones in mind???
February 8, 2017

math
There are lots of online calculators, such as https://www.emathhelp.net/calculators/calculus-2/simpsons-rule-calculator/?f=1%2F%28x%5E5%2B7%29%5E%281%2F3%29&a=0&b=1&n=4&steps=on
February 8, 2017

anonymous
well, how many moles of CO2 in 66.50 grams? Use that and your balanced equation to see how many moles of benzene you need. Then convert back to grams.
February 8, 2017

math
well, you know that 2x = y-14 So, use that in the other equation: -4x = -2(2x), so -2(y-14)-y = 14 ...
February 8, 2017

English
exactly backwards. If the first sentence had to include the "was" then it is a progressive tense: was helping. Becca was {helped/helping} Corky with his homework last night. Similarly, the second sentence is a simple past tense: Blossom watched her best friend study ...
February 8, 2017

Math
28,000(1+2.5) = 98,000 70,000 is 250% of 28000, but that means that it increased by 150%. Gets kinda tricky, if you're not careful with the wording.
February 8, 2017

math
correct, assuming that Jack actually ate his slices ...
February 8, 2017

math
well, just do the math: .05 * 1250 = ?
February 8, 2017

Math
7:4 means the lemonade is 7/11 of the total. 7/11 = .6363 8:4 means 8/12 = .6666 I hope that was the reason you picked C.
February 8, 2017

physics
32@W = <-32,0> 11@N = <0,11> Resultant is <-32,11> = 33.8@W19°N
February 8, 2017

Math
If there are x students in all, 1/4 of the non-band students are in neither: 1/4 (x-12) = x/5 x/4-3 = x/5 x/20 = 3 x = 60 Check: 12 in band, leaves 48 others 36 in dance club 12 in neither
February 8, 2017

math
so, what is "the difference" of a circle?
February 8, 2017

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