Tuesday
May 31, 2016

Posts by steve

Total # Posts: 40,928

Math
well, what is the largest perfect square less than 800? √800 = 28.28 28^2 = 784 800-784 = 16
May 19, 2016

MATH
1.06p = 42.40
May 18, 2016

math
looks like Tn+1 = 2Tn + 2 so, write down the next few terms
May 18, 2016

math
what are the most common integer-sided triangles? 3 4 5 5 12 13 and their multiples.
May 18, 2016

MATH
4(x+1)(x+2) = 24 even without solving the equation, you know that (x+1)(x+2) = 6 so, what two consecutive numbers multiply to 6?
May 18, 2016

math
2(x-3 + 4) = 40
May 18, 2016

help algebra??
#1 - the probability is the same on every draw, since no names are removed when drawing: 80/400 and that's "principal." #2 (x-2+4)^2 + (y+1-6)^2 = 16
May 18, 2016

MATH
a quotient is less than one if the numerator is less than the denominator. So, is 5/6 < 7/8 ?
May 18, 2016

Math
x and 2x-17
May 18, 2016

Math
The global competition for the World Cup is broken into six continental zones. The number of teams in Scottish teams zone is 17 less than twice the number of the teams in the Puerto Rican teams zone. How many teams are in each zone?
May 18, 2016

math
total of 1st set is 12*5.5 total of 2nd set is 8k total of two sets is 20*8.5 so, you have 12*5.5 + 8k = 20*8.5 k = 13
May 18, 2016

Math
clearly not just the average, since that would be 5.5, or slower than Holly by herself. You have to consider how much works gets done in 1 hour by each person. Then you can add that up to see how much gets done together. 1/5 + 1/6 = 11/30 so, the paper takes 30/11 hours for ...
May 18, 2016

calculus
a little algebra. You didn't get that? Show whatcha got.
May 18, 2016

calculus
oops. That should have been ln y = 2lnx + 2x - ln3 - 1/2 ln(2x-5) and also 4x^2-7x-10 in the numerator
May 18, 2016

calculus
I assume you mean y = [x^2 e^(2x)]/ [3√(2x-5)] ln y = 2lnx + 2x - 3/2 ln(2x-5) 1/y y' = 2/x + 2 - 3/(2x-5) 1/y y' = (4x^2-9x-10)/[x(2x-5)] y' = [x^2 e^(2x)]/ [3√(2x-5)] * (4x^2-9x-10)/[x(2x-5)] x e^(2x) (4x^2-7x-10) ----------------------------  &...
May 18, 2016

Geometry
V/v = (R/r)^2 * H/h Not clear just what that ratio is; you garbled the problem.
May 18, 2016

Math
just as a hint, there are 4*2 possible ways to pick the outfit. How many of those have matching colors?
May 18, 2016

physics
could be, but I think there should be a t in there somewhere.
May 18, 2016

maths
the series is the sequence of partial sums. So, the first three terms are 1,5,13 No idea what the last term is, since I don't see a pattern to the items.
May 18, 2016

Algebra I
it means that the change does not depend on the amount already present. The amount changes by a constant amount each time period. That is, a fixed amount per year, per day, etc. So, what do you think?
May 18, 2016

maths
a(r^4-1)/(r-1) = 10 T4/T3 = 1/2 the common ratio is the ratio between any term and the previous one. That should get you started.
May 18, 2016

Math
3*3 = 9
May 18, 2016

Math
there are 3 entrees and 3 veggies. So, since you can pick any entree, and the match it with any veggie, what do you think?
May 18, 2016

Math
false -3 is not a natural number
May 18, 2016

Math
don't know about profit, but the revenue is price * quantity. So, r(x) = 1500x if x <= 150 x(1500-5(x-150)) if x > 150 This is just a parabola with vertex at (225,253125), which is clearly greater than the flat rate for groups of less than 150.
May 18, 2016

Math! Please Check Answers!
I like B, but doesn't a cube have 6 sides?
May 18, 2016

Math
you are correct
May 18, 2016

Math
I assume you know how to find the area of a right triangle. The volume is just base_area * prism_height.
May 18, 2016

Calculus
dx/dt = x^2 Hmmm. if x>1, this will blow up in a hurry
May 18, 2016

Math
Which survey question is biased? “Should the President of the United States serve a six-year term “Which meal—breakfast, lunch, or dinner—is your favorite meal of the day?” “During which month do you prefer to go on vacation?” “Do you ...
May 18, 2016

Calculus
y" = sin(x)+e^(2x) this should be no trouble. Just integrate twice and use the initial conditions to find the two constants.
May 18, 2016

Math
each side is √225
May 18, 2016

Calculus
well, dy/dx = √x/2y 2y dy = √x dx ...
May 18, 2016

Algebra 2 help plsss?
√1296 = 36, so assuming you meant 4√(1296 x^16 y^12) = 4*36x^8y^6 = 144 x^8 y^6 #2 come on. √4 = 2 (4-x)/(x^2+5x-6) ------------------------- = -(x+1)/((x-1)(x-7)) (x^2-11x+28)/(x^2+7x+6)
May 18, 2016

Geometry/math
v = pi r^2 h plug in your numbers
May 18, 2016

Calculus
dx/dy = e^(x+y) dx/dy = e^x * e^y e^-x dx = e^y dy -e^-x = e^y + c x(1) = 0, so 0 = e+c c = -e -e^-x = e^y - e e^-x = e - e^y x = -ln(e - e^y)
May 18, 2016

Math (Check)
me too
May 18, 2016

Geometry
pi * 3^2 * 2
May 18, 2016

Geometry
since (3,0) is on the x-axis, the angle there must be the one bisected by the axis. So, the 3rd vertex is at (6,-4). Now you can find the side lengths and thus the perimeter.
May 18, 2016

math
1680wd/20min = 84wd/min 84/80 = 1.05 or a 5% increase in speed.
May 18, 2016

math
well, 78-8 = 70 ...
May 18, 2016

Mathematics
when you say subtracted by do you mean x-150 or 150-x ? Pick one and set it equal to x/7, then solve for x.
May 18, 2016

math
Assuming you mean that the edge of the cloth is to be trimmed with lace, you want the arc length of the graph. ds^2 = (3cos^2(t)sin(t))^2 + (3sin^2(t)cos(t))^2 dt = 9sin(t)cos(t)(cos(t)+sin(t)) dt integrate that from 0 to pi/2 and multiply that by 4 to get the entire length of...
May 18, 2016

math
4*7
May 18, 2016

math
each term is -2 times the previous one.
May 18, 2016

math
64.1*10^6 / 54*10^4 = 1.19*10^2 = 119 people/mi^2
May 18, 2016

math
start at 8 each term adds 0.5
May 18, 2016

math
B and C are both trinomials. Typo?
May 18, 2016

Math
all the numbers from 1-9 can be formed from the 1st five terms. All multiples of 10 can be formed from the geometric terms (basically just a scaled binary sequence). With that, all the gaps between the tens can be filled with the units.
May 17, 2016

Math (pre-celc 12)
why would you add denominators? These are still just fractions. 1/x = x/(3x+18) multiply by x(3x+18) 3x+18 = x^2 ...
May 17, 2016

ms sue?
.22 + .46 - .10 = .58
May 17, 2016

Algebra 1
The first thing I'd do is multiply by 3 to clear all the fractions: 4s - 9 < 3s + 2 - s 4s - 9 < 2s + 2 2s < 11 s < 11/2
May 17, 2016

integral calculus
∫[0,2] 5x - 5x^2/2 dx
May 17, 2016

calc
3ln2 = ln 2^3 = ln8 by definition, e^lnx = x ln(e^x) = x ln and e^ are inverse functions
May 17, 2016

calc
ln(1/25) = ln(5^-2) = -2 ln(5) e^(3ln2) = e^(ln8) = 8
May 17, 2016

Calculus question ?
nope - just a vertical one
May 17, 2016

word problem math
forget all those decimal points. p+n+d = 9 p+5n+10d = 53 n = d-2 now just solve for p.
May 17, 2016

math
a = kbh a/bh is constant, so you want a such that a/(20*15) = 200/(25*16)
May 17, 2016

Grade 12 Calculus and Vectors
If the dimensions are x and y, then xy = 432, so y = 432/x If the shared side is y, then the cost for our homeowner is c = 2x + y + y/2 = 2x + 3/2 y = 2x + 648/x we want minimum cost, so dc/dx = 2 - 648/x^2 dc/dx = 0 when x = 18 So, the garden is 18x24, with the 24' side ...
May 17, 2016

Algebra II
a 90° clockwise rotation takes (x,y) -> (y,-x) review your rotation matrix definition.
May 17, 2016

Geometry
no idea. what is the relation between the two figures?
May 17, 2016

Math/algebra
what about the formula do you not understand? There are many handy online calculators that you can use to check your answer.
May 17, 2016

maths
2sin(180°+x)sin(90°+x)/cos^4x-sin^4x 2(-sinx)(cosx)/(cos^2x-sin^2x)(cos^2x+sin^2x) -sin2x/cos2x -tan2x
May 17, 2016

math
a = -2 r = -2 T20 = ar^19 = 2^20 = (D)
May 17, 2016

Math
correct
May 17, 2016

Math
the degree is just the highest power of the variable.
May 17, 2016

Math
sounds like the prism is 19x6 by 2 so, there are two bases and two pairs of rectangular lateral faces. It's just a box, and you only have to add up the two areas of the rectangles.
May 17, 2016

Calculus
x+y = 10 p = xy = x(10-x) = 10x-x^2 dp/dx = 10-2x max p at x=5 what a surprise...
May 17, 2016

math
well, is y/x constant? 40/2 is not 20/5 is xy constant? 2*40 is not 5*20 so, neither direct nor inverse. of course, you could have just tried some values in the various choices to check them...
May 17, 2016

Math
not sure what tools you have for estimating polynomial roots, but the signs of the quotient from synthetic division tells you that they are all between -2 and 4. Other than that, some numeric method will have to provide better precision.
May 17, 2016

Algebra
note that each term increases by 5
May 17, 2016

math
if price is p and cost is c, then normally, p = 1.8c If c increases by 20%, then 1.8c - 1.2c = 0.6c that is, the profit has changed from .8c to .6c, or a decrease of 25%.
May 17, 2016

Math
7n-3 = 2n+12 7n = 2n+15 5n = 15 n = 3
May 17, 2016

Science
figure that all the PE has changed to KE
May 17, 2016

math
for a given perimeter, the largest area is enclosed by a square. That is, all 4 sides are equal...
May 17, 2016

Applied calculus
you need Fx = 0 and Fy=0 for a max, so -4x^3 + 2y = 0 -4y^3 + 2x = 0 max f=1/2 at x = y = ±1/√2
May 17, 2016

calculus
z = 1250ln(yx^2)+45(y^2+x)(x^3 -2y)-(xy)^1/2 if x is fixed, dz/dy = 1250/y + 45(2y)(x^3-2y) + 45(y^2+x)(-2) - (1/2)(x)(xy)^(-1/2)
May 17, 2016

calculus
copy/paste font problems garbled the post
May 17, 2016

calculus
well, the distance traveled by the boat is found using d = 280 cot25° - 280 cot 65° speed = distance/time
May 17, 2016

Maths
1/T = 1/60 + 1/30 + 1/15 = 7/60
May 17, 2016

maths
1991 is 4 years from 1987, so the projection is (in billions) 5 * 1.02^4
May 17, 2016

Math
multiply the ratio by 9 and you have 45:18
May 17, 2016

math
using similar triangles, you can see that PH/4 = 18/PH PH^2 = 72 PH^2 + PF^2 = 18^2 PL/4 = PF/PH
May 17, 2016

Percent of loss
523.20 * .192 = ?
May 17, 2016

Geometry
multiply the ratio by 24/5 and you have 72/5 : 24 or 14.4:24
May 16, 2016

science
you are reducing the molarity by a factor of 3, so you need to increase the volume by a factor of 3. 1/3 acid and 2/3 water don't add the acid to the water!
May 16, 2016

Algebra
it lands when h=0. So, just solve the quadratic the way you do normally.
May 16, 2016

science
how long does it take to fall? 4.9t^2 = 30 now use v = 9.8t to get the speed.
May 16, 2016

Physics
it might be, but probably not.
May 16, 2016

math
I suspect a typo. The line from (2,0) to (2,8) is vertical. So, all the other lines must also be vertical or horizontal. They are not. and I think you meant "vertices" of a square...
May 16, 2016

physics
unless you have some idea of the mass of the galaxy, you are stuck. Once you have that, just divide by the sun's mass to see how many "suns" there are in the galaxy.
May 16, 2016

Math
just add up the changes x + 12 + 3 = 44
May 16, 2016

math
well, how many tiles will it take? multiply that by the cost of each tile.
May 16, 2016

maths
start with the sum-to-product formula: sin(√(x+h))-sin(√x) = 2cos((√(x+h)+√x))/2)sin((√(x+h)-√x)/2) or, try substituting u = √x sin(√x) = √x sin(√x) / √x = u * sin(u)/u and you know that lim sin(u)/u = 1
May 16, 2016

Geometry
the distance between those two points is √125 The equation is (x+4)^2 + (y+3)^2 = 125 You have mangled the question somehow. None of the equations has the correct center or radius.
May 16, 2016

maths
Try that again so it makes sense.
May 16, 2016

Mech. Engr./Dynamics/Physics/Math
well, you can start with the observation that the horizontal velocity is constant at v0 * sinθ Now just figure the time needed for each hop, and see if the ball travels enough to skip a step or hit it twice. Of course, you will need to have data on the height and width of...
May 16, 2016

mathematics
if they are the sides of a hexagon, the just add them up.
May 16, 2016

Math
all correct
May 16, 2016

math
7.5" = 10' 10.5" = 14' 10x14 = 140 ft^2
May 16, 2016

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