Thursday
July 30, 2015

Posts by steve


Total # Posts: 32,558

Geometry - incomplete
depending on the labeling, any one of those could work.
June 9, 2015

math
100x + 200y <= 1400 0.6x + 0.8y <= 7.2 x/y >= 2/3 volume is .8x+1.2y Now just follow the usual optimization steps.
June 9, 2015

gwalior glory school
1st digit is 4 ones digit is 2 tens is 2+4 the number is 462 or, 451 if you only have one eye ...
June 9, 2015

math
3n+p = 70 n+3p = 50 add them together and you have 4n+4p = 120 so, 2n+2p = 60
June 9, 2015

Algebra
Just realize that a negative exponent switches the factor between numerator and denominator. (c^-3)^2d^4/d^-2 = c^-6 d^4/d^-2 = d^6/c^6 (e^4)^-3f^-5/f^-2 = e^-12 f^-5/f^-2 = e^-12 f^-3 = 1/(e^12f^3) (8^-7/8)^-2 = (8^-8)^-2 = 8^16
June 9, 2015

MATH
(ar)(ar^3) = 2ar^4 a^2r^4 = 2ar^4 ar^4 = 2r^4 a = 2 a(r^4-1)/(r-1) = 80 1+r+r^2+r^3 = 40 r = 3 So, the GP is 2,6,18,54,162,... (6)(54) = 2*162 2+6+18+54 = 80
June 9, 2015

Algebra
-5c^-3 = -5/c^3 So, (-5/c^3)^4 = 625/c^12
June 9, 2015

Algebra
here's one way. You want the concentration to be reduced by a factor of 15/25 = 3/5 So, the volume must be increased by a factor of 5/3. 5/3 * 120 = 200 ml So, if you add 80ml of water, the concentration is reduced from 25% to 15% Or, you can solve the equation .25*120 + ...
June 9, 2015

maths
factor out the x and you have (5/3 - 3/5)x = (25-9)/15 x = 16/15 x
June 9, 2015

calculus1
The graphs intersect at (0,-1) and (0,1). If this area is spun around the y-axis, you can think of the solid as a bunch of thin discs, of thickness dy, each with a hole in the middle. So, the area is a = ∫[-1,1] π(R^2-r^2) dy where R = 2-2y^2 and r = 1-y^2 a = &#...
June 9, 2015

Calc 1
true If the perimeter is p, then 2x+2y = p y = (p-2x)/2 = p/2 - x The area is a = xy = x(p/2-x) = p/2 x - x^2 This is just a parabola, with vertex at x = p/4 so, y = p/4 as well, and you have a square to get max area.
June 9, 2015

science
I believe it is C water can act as either a polar or nonpolar solvent.
June 9, 2015

Calc 1
what do you mean you "tried 0.5"? Tried for what? In my solution, the slope is 2, not 1/2.
June 9, 2015

Calc 1
clearly, s(0) = 0 s(1/2) = 1 So, the line is y=2t. since t is time and y is position, say, cm, then the slope of the line (cm/s) is the average velocity during the interval [0,0.5] See http://www.wolframalpha.com/input/?i=plot+y%3Dsin%28pi*x%29%2C+y%3D2x
June 9, 2015

Kainantu sec..science(chemistry)
PV=kT That is, PV/T is constant. (10)(1.93)/(273+100) = 1V/273 so just solve for V.
June 9, 2015

Kainantu sec..science(chemistry)
1 mole at STP is 22.4L 2.00g of CS2 is 2/76.14 = 0.0263 moles CS2 CS2+3O2 = CO2 + 2SO2 so, each mole of CS2 produces 2 moles of SO2. I expect you can take it from there...
June 9, 2015

Maths
assuming you measure the 12m along the ground, we have the horizontal distance from the base of the building is 12cos5° = 11.95 So, from eye level, the vertical distance to the top of the building is 11.95tan35°15' = 8.45 Add to that the 1.6m of your height, and ...
June 8, 2015

math
65*3 = 5x x = 39
June 8, 2015

Physics
since s = 1/2 at^2, the truck moved for t seconds, where 42 = 1/2 * 2.15 t^2 t = 6.25 seconds The car moved 1/2 * 3.47 * 6.25^2 = 67.77 meters so, it was 25.77 m behind the truck v = at, so you can figure out the speeds, I expect.
June 8, 2015

Physics
h(t) = 22.0 + 17.0t - 4.9t^2 v(t) = 17.0 - 9.8t So, find t when h=0, and use that to find v at that instant.
June 8, 2015

Physics
x(t) = 2.17+4.80t^2−0.100t^6 v(t) = 2.17+ 9.60t - 0.600t^5 a(t) = 9.6 - 3.0t^4 As you say, v(2) = 0, so a(2) = -38.4
June 8, 2015

algebra
x/(x-5)-3=5/(x-5) x/(x-5)-5/(x-5)=3 (x-5)/(x-5) = 3 1 = 3 not true for any value of x.
June 8, 2015

Maths
since the circumference is πd, just find d where πd*480 = 1200 m
June 8, 2015

geometry
clearly AD and BC are horizontal, and thus parallel. since B is 1 to the left of A, and C is one to the left of D, BA || CD. since AD and AB are not the same length, ABCD is a parallelogram and not a rhombus.
June 8, 2015

Math
can't see the diagram, but the area of a semi-circle is π/2 r^2 So, the area between two semi-circles of radii r and R is π/2 (R^2-r^2) You have circles of radii 14 and 16. So, plug in your numbers.
June 8, 2015

statistics
there were 15 cards, 5 of them diamonds. So, the chance of getting a diamond is 5/15 After that, having drawn a diamond, there are only 14 cards left, 4 of them diamonds. So, the chance that the 2nd draw is another diamond is 4/14.
June 8, 2015

pre calc
y = kx 9 = 12k, so k = 3/4 y = 3/4 x
June 8, 2015

physics
you have a right triangle, with the hypotenuse = 9 (his actual speed), and one leg=2 (the current) so, his resultant velocity must be upstream at an angle x such that sin(x) = 2/9 and the actual resultant speed s (due north) is √(9^2-2^2) Having gotten his speed s, the ...
June 8, 2015

maths
One subset is {1,3} I expect you meant to ask a little more . . .
June 8, 2015

Calculus
the revenue function is price * quantity, so R(x) = x(50-.01x) profit is revenue less cost, so P(x) = R(x)-C(x) = x(50-.01x) - (10+2x) = -0.01x^2 + 48x - 10 Now just set dP/dx=0 and evaluate P there. Or, just use your Algebra I skills and find the vertex of the parabola.
June 8, 2015

math
d/1400 = 8/450
June 8, 2015

Math
The digits are, as explained above, going right to left, 2 3 4*2=8 2+3=5
June 8, 2015

math
Grrrr! The Greek letter is pi The dessert is pie! Here is the graph. I expect you can use it to help with the other questions. http://www.wolframalpha.com/input/?i=-1800cos%289%CF%80%2F6+t%29%2B1800+for+0+%3C%3D+t+%3C%3D+10
June 8, 2015

science
at deceleration a, the velocity is v = 20-at so t = 20/a the distance traveled by the car is s = 20t + 1/2 at^2 = 20(20/a) - 1/2 a (20/a)^2 = 200/a So, to stop in 50 meters, 200/a = 50 a = 4 m/s^2 check: v = 20-4*5 s = 20*5 - 2*5^2 = 100-50 = 50
June 8, 2015

speed time distance
180 km/hr = 50 m/s the front of the train arrives at t=0. The front of the train leaves the platform at t = 365/50 = 7.3 The back of the train whose length is x leaves the platform at t = 7.3 + x/50 So, solve for x in 7.3 + x/50 = 21
June 8, 2015

math
Neither can I. You never asked a question.
June 8, 2015

math
The volume is x(30-2x)^2 The area is (30-2x)^2 + 4x(30-2x)
June 8, 2015

Math
also recall that cos(x) is negative in QII and QIII
June 7, 2015

Pre-Algebra
direct: y = kx, so k = y/x inverse: xy = k If y varies directly with x, find the constant of variation with x = 4 and y = -24 k = y/x = -24/4 = -6 If y varies inversely with x, find the constant of variation with x=5 and y = 10 k = xy = 5*10 = 50 and do the others in like wise.
June 7, 2015

calc
y is concave up if y" > 0 By the 2nd FT of Calculus, y' = -f(x) = -6/(x+1)^2 y" = 12(x+1)^3 so, where is y" positive?
June 7, 2015

Inequalities
Hmmm. I get (x-3)/(x-2) + 12/(x^2-x-2) > 8/(x+1) (x-3)(x+1) + 12 > 8(x-2) x^2-2x-3+12 > 8x-16 x^2-10x+25 > 0 (x-5)^2 > 0 So, all x except x = 2,5 and -1 Oddly enough, it appears that the real solution is x < -1 or x > 2 and x not 5. See http://www....
June 7, 2015

Math (PLEASE HELP!)
Evidently you do not understand the concept of a range. Your temperature is somewhere in 27±3 24 = 27-3 and 30 is 27+3 So, clearly the range is 24-30
June 7, 2015

math
as usual, maximum area is achieved in a square pen. To show this, note that if the dimensions are x and y, we have 2x+2y=200, so y = 100-x The area a = xy = x(100-x) = 100x-x^2 This is just a parabola, with its vertex at x=50. So, the pen is 50x50, or a square. Hmm. I see I ...
June 7, 2015

Math
you want m where 50 < 15+.10m
June 7, 2015

Math
total socks: 7 so, P(blue,red) = 2/7 * 2/7
June 7, 2015

calc
not sure what you mean by evaluate 4-x and 2x-8 Maybe a look at the graphs will help clarify your thinking: http://www.wolframalpha.com/input/?i=plot+y%3D4-x%2C+y%3D2x-8
June 7, 2015

Walk two moons need help
1st question: have you read it?
June 7, 2015

statistics
1569/23652 = 0.06633 You can do the rounding.
June 7, 2015

statistics
176/232 = 0.75862 You can round that as needed.
June 7, 2015

Statistics
since the yearly salary amounts to 2080*13.50 the benefits amount to 24% of that amount.
June 7, 2015

algebra
y = (10x+7)/(6x+3) now solve for x: (6x+3)y = 10x+7 6xy+3y = 10x+7 (6y-10)x = 7-3y x = (7-3y)/(6y-10) now x is y^-1, so to express f^-1(x), that is f^-1(x) = (7-3x)/(6x-10)
June 7, 2015

Algebra
for the survey, (b) looks better to me for the poems, you have (4/13)(2/12)
June 7, 2015

Algebra
(1.4*8)x10^(1+4) = 11.2x10^5 = 1.12x10^6
June 7, 2015

Math
if the base is x and the height is z, then x^2z = 4 The surface is the base and 4 sides, so a = x^2 + 4xz = x^2 + 4x(4/x^2) = x^2 + 16/x da/dx = 2x - 16/x^2 = (2x^3-16)/x^2 da/dx = 0 when x=2, so the container is 2x2x1
June 6, 2015

Math (PLEASE HELP!)
T = 27±3 |T-27| <= 3 Surely you can figure the range.
June 6, 2015

Math
1/7 = 3/(4x-1) 1 = 21/(4x-1) 4x-1 = 21 4x = 22 x = 11/2
June 6, 2015

Math/Physics
just given arbitrary vectors of some magnitudes, there is no way to compute their sum or difference. Unless you know the x- and y-components, you are stuck.
June 6, 2015

Algebra
x(x+18) <= 175 x^2+18x-175 <= 0 (x+25)(x-7) <= 0 So, -25 <= x <= 7 Or, for real-world tables, 0 <= x <= 7 There is probably a minimum positive width for a useful table.
June 6, 2015

math
The 4th row of Pascal's Triangle is 1 4 6 4 1 That is, (a+b)^4 = a^4 + 4a^3b + 6a^2b^2 + 4ab^3 + b^4 So, (3+b)^4 is 3^4 + 4(3^3)b + 6(3^2)b^2 + 4(3^1)b^3 + b^4 = 81 + 108b + 54b^2 + 12b^3 + b^4 That's all very nice, but if your question is to solve for b in (3+b)^4 = 1...
June 6, 2015

algebra
when you raise to powers, you multiply exponents. Consider: 2^3 = 2*2*2 (2^3)^4 = (2*2*2)*(2*2*2)*(2*2*2)*(2*2*2) = 2^(3+3+3+3) 2^(3*4) = 2^12 So, (x^4 y^5)^5 = x^20 y^25
June 6, 2015

Math
1/4 + 1/s = 1/3 Now just solve for s.
June 6, 2015

algebra
6C3 = (6*5*4)/(3*2*1) = 20
June 6, 2015

math
Draw radii to the points of tangency. Draw a line connecting the centers. Draw a parallel line, 2 units closer to the tangent points. Now you have a right triangle with legs 10 and 6, with the tangent line forming the hypotenuse.
June 6, 2015

math
It won't seem hard after you've done a few dozen of them... I assume you meant 9^(x+2)=240+9^x That is the same as 9^2*9^x = 240 + 9^x 9^x(81-1) = 240 80*9^x = 240 9^x = 3 x = 1/2
June 6, 2015

Math
make that 2n/10 + 5n/7 + 303 = n
June 6, 2015

Math
"several" sevenths? What kind of nonsense is that? Anyway if that means 5/7, then 2/10 + 5n/7 + 303 = n n = 3535
June 6, 2015

math
angle ADB is an exterior angle to triangle ACD. So, it is equal to angles ACD+CAD. Thus angle C is 45 degrees.
June 6, 2015

Math
In the absence of any other information about how the amplitude changes, I'd just use a linear rate of change. For instance, y = (2+0.3x) sin(x) Or, if you insist on a constant amplitude, then averaging them seems like a good option.
June 6, 2015

Math
Assuming even change in height, the rate is 0.5 m/hr So, at what time t do you have 1.4 + 0.5t = 1.71 ??
June 6, 2015

Math
see your original post.
June 6, 2015

math derivatives - eh?
The given information says nothing about the height or width of the building. Without that, we do not know enough to work the problem.
June 6, 2015

Math
see your previous post.
June 6, 2015

Math
come on, man! The common difference is A2-A1 or A3-A2, which they gave you. The difference is shown above: -2p+10 or -3p-13 In either case, it is 56. Now do you think you can write the sequence?
June 6, 2015

Math
since the difference is constant, (5p+12) - (7p+2) = (2p-1) - (5p+12) -2p+10 = -3p-13 p = -23 Now you can find the difference, and write the terms of the sequence.
June 6, 2015

Algebra II
that it is.
June 6, 2015

math
you want, for m miles, 26+.12m = 24+.19m
June 5, 2015

math
a quadratic has x^2 as its highest power. So, A. Note that y decreases by 3 when x increases by 1. So, it will look like y = -3x But, when x=0, -3x=0, and y is -8. So, y = -3x-8 again, A
June 5, 2015

Math- algebra
the colony doubles 4 times every hour. So, after t hours, it has reached 2^(4t) cells. Clearly 4t = 13
June 5, 2015

Geometry
Since triangle DEC is a right triangle, with angle C = 30° and DC=10√3, DE = 10. No idea what the "length" of E is, since it's a point.
June 5, 2015

Math
24/8 = 3 x^4/x^-3 = x^7 z^-2/z = z^-3 Looks like C to me
June 5, 2015

Basic Differential Equation
You have (D^2+16)y = 0 so the solutions are e^(±4ix) or sin and cos (sin 4x)" = -16sin(4x) (cos 4x)" = -16cos(4x) If the answer is just sin(4x) then there must be some other conditions
June 5, 2015

math
you can choose each scoop 5 ways, so 5^3=125
June 5, 2015

Math
multiply by r and you have r^2 = -2rcosø-2rsinø x^2+y^2 = -2x-2y x^2+2x + y^2+2y = 0 (x+1)^2 + (y+1)^2 = 2
June 5, 2015

geometry
4'6" = 54" 9'7" = 115" so the scale is 115/54
June 5, 2015

Algebra help
you want the area of the deck-and-pool to be 832ft^2 greater than just the pool. So, solve for w in (w+8)(3w+8) - 3w^2 = 832 Having gotten w, you can now determine the size of the pool. Sounds to me like the problem is poorly stated. You already know the size of the pool. You ...
June 5, 2015

math
1 3/4 = 7/4 7/4 * 9 = ?
June 5, 2015

math
1 4/5 = 9/5 2/(9/5) * 7 and round up to a whole bottle
June 5, 2015

Math
"larger than" means you subtract, to find the difference. So, you have ((-1)^2 + (-2)^2 + 5^2) - (-1-2+5)
June 5, 2015

Math
Can you factor x^2+x-12? This will be very like that.
June 5, 2015

Math of class-10
∜3 is a root of the equation x^4 - 3 = 0 Using the Rational Root Theorem, any rational roots p/q of that equation must have denominator of 1, and numerator a divisor of 3. Since 3 and 1 are not roots, there are no rational roots.
June 5, 2015

Calculus
Looks like the curve y=e^x on the interval [2,7] rotated around the line x=1. I assume you meant to include dx in the integral. Since the volume of a shell of thickness dx is 2πrh dx, if r = x-1 and h=e^x that fits the bill.
June 5, 2015

Math
(1/2)(3/5) + (1/2)(2/6)
June 5, 2015

algebra
w(2w+2) = 312 Now solve for w.
June 5, 2015

Math
well, geez. Midnight to 10 am is not exactly a full day, now, is it? Most folks are sleeping during most of that period. When you ask "which" it implies that we be given a list to choose from. Maybe we were waiting for you to see that you had not supplied any choices...
June 4, 2015

Math
if sides a and b are equal, then a/sinA = b/sinB means that a/sinA = a/sinB so sinA = sinB Now, A and B need not be equal if their sines are equal, but in that case A = 180°-B and your triangle is just a flat line.
June 4, 2015

math
well, that would be when 20sin 2pi/40 (t-10) + 21 = 15 20sin 2pi/40 (t-10) = -6 sin 2pi/40 (t-10) = -.30 sin .304 = .3, so 2pi/40 (t-10) = pi+.304 or 2pi-.304 t = 31.935 or 48.065 or other values periods away.
June 4, 2015

math
domain is naturally all reals vertical shift is -1, so range is -1-2 to -1+2 amplitude is 2 period is 2pi/3 phase shift is -180
June 4, 2015

Math
First, disambiguate your expression. As it is written, it means (1/6^8)/3 - 2/3 = -3359231/5038848 or do you mean 1/6^(8/3) - 2/3 = 1/∛1679616 - 2/3 or something else entirely? Formatting is not the browser's forte.
June 4, 2015

Math
so she needs a circle of radius 3 (9π) and a rectangle which is 6πx12.
June 4, 2015

Algebra II
Your first step is wrong. Just subtract b². It should be 4b = 3b² 3b² - 4b = 0 b(3b-4) = 0 b=0 or b=4/3 b = -4/3 should immediately be seen not to work, since you have b² + 4b = 4b² If b is negative, there is no way you could subtract something from b&...
June 4, 2015

  1. Pages:
  2. <<Prev
  3. 2
  4. 3
  5. 4
  6. 5
  7. 6
  8. 7
  9. 8
  10. 9
  11. 10
  12. 11
  13. 12
  14. 13
  15. 14
  16. 15
  17. 16
  18. Next>>

Members