Friday
May 22, 2015

Posts by STEVE


Total # Posts: 31,324

math
experimental loaded dice!
May 22, 2015

math
the vertex of ax^2+bx+c is at x = -b/2a In this case, that is 750/50 = 15, not 9. v(15) = 4375
May 22, 2015

math
well, that would just be the difference between the two temperatures. How do you find the difference between two numbers? For example, how much bigger is 100 that 20?
May 21, 2015

Physics
I see a lot of verbage, but nothing related to actually solving this problem. Draw a diagram of the vectors involved. Clearly, sin α = 10/80, so α = 7.18° The speed at touchdown will be 80 cosα = 79.37 mi/hr
May 21, 2015

Physics
nope: C 1/20 = 1/8 + 1/x x = -13.3
May 21, 2015

Math
stupid cursing filters! 8/2 = 4 cages of c**katiels 32/10=3.2, so 4 cages of parakeets 28/10=2.8, so 3 cages of finches
May 21, 2015

Math
ooops. negative multiplication changes direction: -2x < 9 x > 9/-2 x > -4.5
May 21, 2015

math
see related questions below
May 21, 2015

algebra
original amount: x apples Becky gets (x+1)/2, leaving Joy (x-1)/2 Gayle gets (x+1)/4, leaving Joy (x-3)/4 Bonnie gets (x+1)/8, leaving 1 left over x - (x+1)/2 - (x+1)/4 - (x+1)/8 = 1 x = 15 or, working backwards, there were ((1*2+1)*2+1)*2+1 = 15 apples to start
May 21, 2015

MATH PRACTICE
if you look at the coordinates, you just have a right triangle, with legs of length 4 and 7. So, figure the hypotenuse and add 'em up. I get something close to 19.
May 21, 2015

Algebra
√(1/5) - √5 1/√5 - √5 (1 - √5√5)/√5 (1 - 5)/√5 -4/√5
May 21, 2015

Zoneton
formatting. Should have been -2x < 9 x > ??? Swap sides to get -9 < 2x -9/2 < x or, x > -9/2
May 21, 2015

Math.
Clearly you need to review your shapes and their volumes. v = pi/3 r^2 h r=12 and h=10, so v = 3.14/3 * 12^2 * 10 = 1507.2 in^3
May 21, 2015

English
not necessarily. #2 is just motion #1 also implies intent -- to eat you.
May 21, 2015

Maths
well, which of them tends to oscillate between a max and a min on a regular (say, daily) basis?
May 21, 2015

math
mean
May 21, 2015

Calculus and quadratic equations
The data points are: (0,10000), (3,7075), (6,6400), (9,5275) The instructions say: If the last digit of your Student ID No. is an integer power of 2, then you are to use the initial investment value and data from 3 weeks and 6 weeks to work out the model. So, now you know ...
May 20, 2015

math
looks like 6 to me there are 3 ways to make the first move. Then from the new corner, there are 2 ways to continue. Then there is a single last move.
May 20, 2015

physics
the horizontal speed is 17.32 m/s So, the package falls for 750/17.32 = 43.30 seconds So, you need h where h + 10.0t - 4.9t^2 = 0 and t = 43.3 Now you can carry on with the other parts,
May 20, 2015

English
The expression is "have it easy." similarly expressions: Some like it hot. I can't get it right. Using "easily" would indicate the having, rather than what is being had. (Also, I've never heard anyone say it!)
May 20, 2015

Geometry
I'd say the distance formula, given the definition of a parabola.
May 20, 2015

Trig - My Bad
I messed up on my sign (QII) So, Reiny, how did you get 5/12? That was -tanØ
May 20, 2015

Trig
Not sure I like your values: sin2θ = 2sinθcosθ = 2(-5/13)(-12/13) = 120/169 cos2θ = 2cos^2θ-1 = 2(144/169)-1 = 119/169 tan2θ = sin2θ/cos2θ = 120/119
May 20, 2015

Trig
since π < θ < 3π/2 (QIII), sinθ = -5/13 tanθ = 5/12 Now just plug those into your double-angle formulae.
May 20, 2015

PHYSICS
so, what are your calculations? Maybe we can figure out what's wrong.
May 20, 2015

L A/The Giver
I agree with #1 Have you read the other two books in the series? Good story.
May 20, 2015

math
If the loan is for 62 days, then you want just 62/360 of the 15% for interest, since it's 15% for a whole year. (assuming the 360-day year)
May 20, 2015

math
I assume you want just the region in QI, since otherwise the axis of rotation is inside part of the region. So, we want the area whose vertices are (0,0), (0,1) and (π/2,π/2) Around the x-axis, we have, using discs, v = ∫[0,π/2] π ((x+cosx)^2 - x^2) ...
May 20, 2015

help
x + 3x = 20 . . .
May 20, 2015

physics
No.
May 20, 2015

math
to find the # of children's tickets, you just solve 35(2c) + 20c = 1890 then double that for the adults.
May 20, 2015

Good call, Reiny
Yes, I neglected to mention excluded values. One cannot gloss over stuff like that. My bad.
May 20, 2015

algebra
x/(6x-x^2) = x / x(6-x) = 1/(6-x) (x^2 - 3x - 18) / (x + 3) = (x-5)(x+3)/(x+3) = x-5 (k+3)/(4k-2) * (12k^2+2k-4) = (k+3)/(2(2k-1)) * 2(2k-1)(3k+2) = (k+3)/(3k+2)
May 20, 2015

math
if there's a 20% discount, it sells for 80% of its original price. so, 0.80 p = 126.40
May 20, 2015

math
well, geez, just check your answer 11 dimes and 2 nickels does indeed add up to $1.20
May 20, 2015

math
add up the coins: n+d = 13 add up the values: 5n+10d = 120 Now just solve for n and d.
May 20, 2015

Algebra
(8m^7 - 10m^5) / 2m^3 = 8m^7/2m^3 - 10m^5/2m^3 = 4m^4 - 5m^2 -2/(x+3) - 4/(x-5) = [-2(x-5) - 4(x+3)] / (x+3)(x-5) . . . 7/(x-3) + 3/(x-5) = [7(x-5) + 3(x-3)] / (x+5)(x-3) . . . -1/(x-9) - -2/(x+7) = [-(x+7) + 2(x-9)] / (x-9)(x+7) . . .
May 20, 2015

Trig
correct.
May 20, 2015

algebra
yes, it appears to be an exercise in the distributive property. Do you have a question? I expect you need to use the property to get rid of the parentheses and then solve for the variables. What do you get?
May 20, 2015

Statistics
so, at 5% per period, after 6 periods, the account will have 2000*1.05^6 + 2000*1.05^5 + ... + 2000 = 2000(1.05^7 - 1)/0.05 = 16284.02
May 20, 2015

geometry
well, v = 1/3 πr^2 h so, unless you know something about the height, there's no way to pin down the radius. All you know for sure is that r^3 h = 960/π Maybe you can fix things and then solve for r. Please don't just come back and say h=5, so what's r? ...
May 20, 2015

CSIR General Aptitude
Just subtract the starting position from the ending position to get the distance traveled...
May 20, 2015

pre-algebra
9z+8+3(2-4z)-9=-40 9z+8+6-12z-9 = -40 -3z+5 = -40 -3z = -45 z = 15
May 20, 2015

math
I assume you meant exactly 2 standard deviations above the mean So, 2 std's = 8, making the mean 85-8 = 77
May 20, 2015

Maths
so, what's wrong with that as an answer? That's what I get, too. http://www.wolframalpha.com/input/?i=1%2F%281%2F%281%2B2i%29+%2B+1%2F%282%2B5i%29%29
May 20, 2015

Math Check Answers Quickly Please
both are correct.
May 20, 2015

math
If the base is a n-gon, then the base has n sides and n vertices. So, clearly the pyramid has n lateral faces and edges, no?
May 20, 2015

Maths
depends on the tools you have learned. Most easily, use a calculator. figure 18*3.14159/5.86 and then hit the sin button. Make sure you are in radian mode.
May 20, 2015

math
have you no calculator? If not, you can just enter that text into the google search box, and it will give you the result.
May 20, 2015

science
check the label to see the expected delay.
May 20, 2015

Math
5m+13
May 19, 2015

algebra2
That file exists only on your computer. No way for us to open it. Best suggestion: review the properties and work it out. Next best: tell us the question for some help.
May 19, 2015

Math
you can find the distance PQ using the law of cosines: x^2 = 10^2 + 6^2 - 2(10)(6)cos137° x = 14.959 for the bearing, locate P and Q in rectangular coordinates and then the bearing is 90-arctan(y/x) where x and y are the corresponding displacements from Q to P.
May 19, 2015

Algebra 2 Honors
you can get that without worrying about k. since r = kst, r/st = k and is constant. So, you need s in 140/(-5*20) = 7/(2.5s) s = -2 as you calculated
May 19, 2015

algebra
-1/(x-9) - -2/(x+7) -1(x+7) - (-2)(x-9) ------------------------- (x-9)(x+7) (-x-7+2x-18) / (x-9)(x+7) (x-25) / (x-9)(x+7)
May 19, 2015

algebra
a/b/c (a/b)/c = a/(bc) So just plug in your values and reduce.
May 19, 2015

Calculus
1. I get = π[(1/4)y^2 + y] from -2 to 1 = π((1/4+1)-(1-2)) = 9π/4 2. I get 9π/4 also making the total volume 9π/2
May 19, 2015

Calculus
suppose ∫ f(x) dx = F(x) Then ∫[0,8] f(x) dx = F(8)-F(0) = 4 ∫[0,2] f(4x) dx = ∫[0,2] 1/4 f(4x) d(4x) = 1/4(F(8)-F(0)) = 1 check: ∫[0,8] x^2 dx = 512/3 ∫[0,2] (4x)^2 dx = 16(8/3) = 128/3
May 19, 2015

math please help
the perimeter is just the sum of all the sides. So, for the large triangle, p = 4x+2 + 7x+7 + 5x-4 = 16x+5 Now do the same for the smaller triangle. For (B), just subtract one expression from the other.
May 19, 2015

Calculus
how about |x^2-cosx| or, 2*integral from 0 to 2, since both cosx and x^2 are even?
May 19, 2015

Calculas
the volume of a disc of thickness k is pi r^2 k If the radius is y, it means you are rotating around the x-axis, so the volume of each disc is pi y^2 dx If rotating around the y-axis, each disc's radius is x, so the volume is pi x^2 dy Try drawing a diagram, guys. As you ...
May 19, 2015

Calculas
pi y^2 is used when rotating around the x-axis.
May 19, 2015

Calculas
if you use discs, they have holes. Shells are just like nested cylinders, so there are no holes. Using discs (washers), the calculation is more complex, since the lower portion is bounded by the y-axis (solid discs), and the upper portion is bounded by the two curves (washers ...
May 19, 2015

Calculus
The curves intersect at (±√3,4) So, using the area in the first quadrant, we have, using shells, v = ∫[0,√3] 2πrh dx where r=x and h=(x^2+1)-(2x^2-2)=(3-x^2) v = 2π∫[0,√3] x(3-x^2) dx = 9π/2 Looks more like a bowl than a vase...
May 19, 2015

Calculus
because f(-x) = -f(x) There is equal area above and below the x-axis.
May 19, 2015

Quadratic Functions and Calculus
Holy crap! Have you done anything on this? Have you determined the three data points to use? Have you decided what to do using the ID number? Come back with some input, ok?
May 19, 2015

Quadratic Functions
Not sure what BiQuad is, but if you want to fit a parabola through those three points, you have, assuming that v(t) = at^2 + bt + c, 0a+0b+c = 10000 9a+3b+c = 2025 36a+6b+c = 6400 Somehow I suspect what you really wanted was v(3) = 1000-2025 = 7975, since most stocks don't...
May 19, 2015

math
well, shoot. Which is bigger: a ft^3 or a yd^3?
May 19, 2015

math please help
they are the same. It shows why 11^0 = 1 or why x^0 = 1 for any value of x. (except x=0)
May 19, 2015

math help please!!
3^3/3^6 = 3*3*3 ----------------- 3*3*3*3*3*3 Now you can see that three 3's cancel out in top and bottom, so you are left with 1/(3*3*3) = 1/27 This shows why x^n / x^m = x^(n-m)
May 19, 2015

Math
can you try that again in English?
May 19, 2015

Math
the cars are 360/16 = 22.5° apart. car 16 is 3 positions from car 13. So, a rotation of 67.5° will move car 16 to car 13's position.
May 18, 2015

geometry
in a triangle, angles are opposite sides. Two angles cannot be opposite each other. Using the tan function, the hypotenuse is not used. If the base 12 is opposite the 71° angle, then 12/d = sin 71° 12/c = tan 71° Better review your trig function definitions.
May 18, 2015

Math
you have a rectangle that is 100x(40+20) and a circle that has diameter 40+20=60 so, just add those two areas. If the area inside the circular ends but outside the rectangle does not count, then you have to subtract off the smaller circle of diameter 40.
May 18, 2015

Math
a^2 = 6 b^2 = 5 c^2 = a^2+b^2
May 18, 2015

Math
you want x minutes, where 12+.05(x-500) = 10+.04(x-300) x = 1100
May 18, 2015

math
each interval has width 2, so the midpoints are at 1,3,5,7,9
May 18, 2015

math
16-x^2 is concave down, so you want to use the right endpoints. Each interval has width 1, so you just have 2(f(1)+f(2)+f(3)) = 2(15+12+7) = 68 There are several good online Riemann Sum calculators. You can use them to verify your work.
May 18, 2015

math
see related questions below
May 18, 2015

math
just plug in the values for n: t1 = 7 t2 = 2t1-3(2) = 2(7)-3(2) = 8 t3 = 2(8)-3(3) = 7 ...
May 18, 2015

math
so, did you use the formula?
May 18, 2015

algebra 2 and trig
how many std's away is the 2.5% boundary? The mean is at (78+92)/2 = 85
May 18, 2015

Calculus
Assuming x is not zero, the fractions are zero when the numerators are zero. So, f'=0 when 8x+1 = 0, or x = -1/8 f"=0 when 4x-1 = 0, or x = 1/4
May 18, 2015

Algebra 2
revenue for x hats is y=15x cost is y=0.4(x-150)^2+9000 So, you want x when 15x >= 0.4(x-150)^2+9000 x >= 262.5 so, at least 263 hats
May 18, 2015

Math
if the chord length is 2x, then half the chord subtends half the angle: x/200 = sin 34°
May 18, 2015

please help math
it is that.
May 18, 2015

math please help
after n years, its value is 400(1.07)^n
May 18, 2015

Calculus
it reverses direction when its velocity changes sign. That is, when v(t) = 0. So, find t when v(t) = s'(t) = 3t^2 - 18t + 24 = 0 then plug that value into s(t) and a(t)
May 18, 2015

Math
he used 15.75-10.5 = 5.25 gallons of paint in 1.5 hours. That is 3.5 gal/hr Thus, using the point-slope form of the line, if y is the amount of paint left at x hours after 12:00, then y-10.5 = -3.5(x-2) So, find y when x=0. Or, knowing that he used 3.5 gal/hr, and knowing that...
May 18, 2015

math please
when dividing numbers expressed as powers, you subtract the exponents. Think about it 10^7/10^3 = 10*10*10*10*10*10*10 --------------------------- 10*10*10 Three of the factors cancel, and you are left with 7-3 = 4 multiples of 10. That is 10^(7-3) = 10^4 So, you want (C)
May 18, 2015

Math
216 = 6*6^2 96 = 6*4^2 so, you wind up with 6√6t + 4√6t = 10√6t = √600t
May 18, 2015

Algebra
a = w(w+4) . . .
May 18, 2015

MATH if work is correct
78125 = -5^7 So, starting with 5^-2, the 10th term is -5^7 Note that the 3rd term is 1=5^0. So, you have to multiply by -5 another 7 times to get to -5^7.
May 18, 2015

Math
the full volume is 60*60*45 2/3 of that is still empty. So, divide that volume by 6 L/min (6000 cm^3/min) to get the time needed.
May 18, 2015

Math
In how many different orders can you read 4 books
May 18, 2015

science
a body of mass 5kg is thrown to a height of 100m.what is its potential energy at the maximum height.?
May 18, 2015

math Help!!!!
There are 6 ways you can draw the two marbles to include one red: RB,RY,RW,BR,YR,WR There are 4P2 = 12 ways to draw any two marbles So, P(one red) = 6/12 = 1/2
May 18, 2015

math...Please help!!!!
I think B, but the language is garbled. The SD will not change. Read up on how the SD is figured, and you should see why.
May 18, 2015

Geometry
h^2 + 7^2 = 28^2
May 18, 2015

Math
as you recall, if the axes are rotated through θ, tan 2θ = B/(A-C) so, tan 2θ = 24/7 and cosθ = 3/5 sinθ = 4/5 Now just plug those values into your rotation matrix and crank it out.
May 18, 2015

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