Thursday
September 29, 2016

Posts by Steve

Total # Posts: 44,207

Math
as long as each x value appears only once, it is probably a function. So, I'd pick A and B on that basis. D also works. While 0 appears twice as the first element, the 2nd element is the same. So, the pair (0,3) appears twice, but it does not violate the rules for functions.
September 8, 2016

Math
8 + 6/2 = 11
September 8, 2016

math
v = at so, how long does it take to fall 685 ft?
September 8, 2016

Math
not sure what each watermelon with 12.73 inches and 2.7 inches in height means
September 8, 2016

Algebra
3*84 <= 81+87+x <= 3*89 254 <= 168+x <= 267 ...
September 8, 2016

Algebra
since distance = speed * time, 20x = (20-4)x + 6 and I think you meant "downwind"
September 8, 2016

Math
correct. If you type in your expressions at wolframalpha.com you can check your answers quickly. For example, http://www.wolframalpha.com/input/?i=2+1%2F7+divided+by+3+2%2F3
September 8, 2016

math
That's h of x, not h times x. h(x) = √(4-x^2)/(x-3) or h(x) = √((4-x^2)/(x-3)) In either case, x=3 is excluded because the denominator is zero. Now, √z has a domain of z>=0. In the first case, 4-x^2 >= 0, so x^2 <= 4 |x| <= 2 In the second ...
September 8, 2016

Maths
roughly 0.6 * 150
September 8, 2016

Algebra 2
15000/3500 = ? round up to next whole bucket
September 8, 2016

Technology
correct
September 8, 2016

Math
just write down the parts and add them up
September 8, 2016

Algebra
well, 7^2 = 49 8^2 = 64 So, it's either 7 or 8, but now you gotta figure which one.
September 8, 2016

Math
oh, well, 1 3/7 = 1+3/7 = 7/7 + 3/7 = 10/7
September 8, 2016

Math
well, the idea is right, but 3/7 = 15/35 Then, do just what you did with the previous problem: 15/35 - 38/35 = -23/35 Plus, you misspelled "to"
September 8, 2016

math
yes.
September 8, 2016

math
huh? This is exactly like the last one; just use different numbers. What do you get?
September 8, 2016

math
c = t+60 t = 2/3 c or, t = 2/3 (t+60)
September 8, 2016

Math
hey, it's nice to see a problem posted that shows some thought and effort.
September 8, 2016

Math
yep
September 8, 2016

Math
for sphere, v = 4π/3 r^3 for cylinder, v = πr^2h so, since the radius of the cylinder is 1, 4π/3 (1^3+2^3) = πh
September 8, 2016

Math
draw a diagram. The diagonal of the square is the diameter of the circle. Knowing that, you can figure the area of the square.
September 8, 2016

science
#1 Really, lattices are found in crystals. (Plus, why would that be affected by a charged balloon?) #2 C looks good to me.
September 8, 2016

Math
google is your friend. just search for equilateral triangle. If the side is s, then perimeter = 3s area = √3/4 s^2
September 8, 2016

Mathematics
(3 5/7)x = 3 1/4 (26/7)x = 13/4 x = 13/4 * 7/26 = 13/26 * 7/4 = 1/2 * 7/4 = 7/8
September 8, 2016

Math
total points for 4 tests @ 96 = 384 points so far: 94+98+98 so, how many does he need on the last exam? Hint: 96 is the average of 94 and 98
September 8, 2016

Science
a magnet will get the iron oil floats on water evaporate the water to get salt
September 8, 2016

physics
The larger car is the Mercedes-Benz.
September 8, 2016

Maths
Drop altitudes from C and D. That will create a rectangle and two right triangles. I'm sure you can find those areas. Don't forget the Pythagorean Theorem to find the altitude.
September 8, 2016

Algebra2
Draw the lines y = 4x-1 y = 3x-1 Shade everything below the 1st, and above the 2nd. The intersection of the two shaded areas is the solution set
September 8, 2016

Algebra2
Solve the inequalities by graphing y<=4x-1 y>3x-1
September 8, 2016

Math
2/3 X 21 2 x 7 14
September 8, 2016

AAHHOOOOGAH! Homework Dump!
how about showing some of your ideas on any one of the problems?
September 8, 2016

Math
how can a rectangle have three such ratios? If 3:4, then the width is 3x and the length is 4x, and we have 2(3x+4x) = 70
September 8, 2016

Calculus
Riemann sums, trapezoidal method. google numerical integration or quadrature
September 8, 2016

Calculus
I don't see any way, other than numerical approximations. The velocity is not a nice linear function, so only an integral can give an exact answer ∫[0,14] (11+6cosx) dx
September 8, 2016

MATHS
dC/dx = 600 - 180000/x^2 plug in x=100 I assume C(x) is the income function
September 8, 2016

math
ummm, 33*41 ?
September 7, 2016

Math
You have the right idea re add 6.75 + 3.5 = 10.25 not 10.35 you have the right process to get per hr $92.25/10.25 =$9 per hr
September 7, 2016

Pre algebra
a rational number is what you know as a fraction. It is the ratio of two whole numbers. 3/4, -7/11, etc. An integer is a rational number with a denominator of 1. Or, more commonly just what you think of as a counting number, but may be negative: 3/1 = 3 -2/1 = -2 and so on An ...
September 7, 2016

math
(1/20000)^2 * 50 km^2
September 7, 2016

Math
You have 8 3.4 gal of paint you're going to use 2/5 of it to paint what type of math would you use to figure how much? Multiplication!! 8 3/4 times 2/5 = see if you can get it from there
September 7, 2016

MATH...please help
If $x is at 5%, then the rest (10000-x) is at 6%. The interest of both parts must add up to 575: .05x + .06(1000-x) = 575
September 7, 2016

Algebra HELP!
when it says substitution, use the value from one equation to solve the other. y = 2x-1, so the 2nd equation becomes 2x+2(2x-1) = 22 2x + 4x - 2 = 22 6x = 24 x = 4 Using elimination, find ways to make one variable disappear by adding the two equations (or multiples of them) 5x...
September 7, 2016

Advance Math
well, 45° is 1/8 of a circle. So, the volume is 1/8 of the whole.
September 7, 2016

Math
If the fraction is x/(x+1), then we are told (x+1)/x = 3/4 + 7/12
September 7, 2016

Algebra ll
well, what is the minimum number of tellers?
September 7, 2016

Calculus integrals
there are nice online Riemann sum calculators so you can check your work >wink wink<
September 7, 2016

Math
hundreds
September 7, 2016

math
seven times a number: 7x difference between 18 and 7x: 18-7x Think you can take it from there?
September 7, 2016

Calculus
I'm sure you can make the table. You know that sinu/u -> 1 as u ->0 since cos(0) = 1, that means that tanu/u -> 1 as u -> 0 You have tan3x/7x = tan3x / (3x)*(7/3) = (tan3x/3x) * 3/7 so, what do you think the limit is?
September 7, 2016

Math
assuming that "t" means "+", 4a+a+a = 4a + 1a + 1a = (4+1+1)a = 6a the a's add up just as 4 oranges + 1 orange + 1 orange = 6 oranges 4+1+1 of anything make 6 of that thing. In this case, "a"
September 7, 2016

Math - vectors
LCM(4,14) = 28 So, 7r = 28i + 7tj 2s = 28i - 24j so, if 7t = -24, 2s = 7r, so one is a multiple of the other. Or, more directly, 14/4 r = 14i + 14/4 t j so, if 14/4 t = -12, s is a multiple of r.
September 7, 2016

Science
you know that gravity provides constant acceleration. That means the the velocity grows by the same amount in equal time periods. That is why g = 9.8 m/s^2 That means g = (9.8m/s)/s Or, v grows by 9.8 m/s every second. So, if v=9.8t after t seconds, then you want t where 9.8t...
September 7, 2016

Math
naturally, (2x+7)^3 just expand that out.
September 7, 2016

Math III Honors
note that at each break point, the base amount is the maximum tax of the previous bracket. That means that for income <= 6000 max tax is 600 <= 27950 max tax is 3892 <= 67700 max tax is 3892.50 So, tax of 4446 means that income was between 27950 and 67700 3892 + .27(x...
September 7, 2016

Math
pairs where y=0 are on the x-axis pairs with x=0 lie on the y-axis
September 7, 2016

Math
if his age now is x, then Four more than twice Jason's age is 2x+4 now do the other, set them equal, and find x.
September 7, 2016

6th grade plz help
"more than" means you add 4+2 is 2 more than 4 so, now what do you think is 15 more than d?
September 7, 2016

Algebra
It's not very clear just what you have...
September 7, 2016

Maths - Bogus
do as with all inductions. show that it's true for n=1 sinx = sin^2(x)/sin3x Nope, not true. So, how about n=2? sinx+sin3x = sin^2(2x)/sin3x Nope. Better fix this and come back.
September 7, 2016

Geometry
It has to do with so-called addition property of equality and division property of equality. Basically, if two things are equal, adding or dividing both things by the same amount does not affect their equality.
September 7, 2016

math
after x hours after 2PM, you want 500x + 550(x-2) = 3100
September 7, 2016

geometry
if every dimension, including the height is doubled, then the area grows by a factor of 4.
September 7, 2016

Math, Calc
x^2+2xy+4y^2=12 2x + 2y + 2xy' + 8yy' = 0 (x+4y)y' = -x-y y' = -(x+y)/(x+4y) at (2,1) y' = -1/2 so, the line is y-1 = -1/2 (x-2)
September 7, 2016

Math (urgent)
Looks good to me
September 7, 2016

Math (urgent)
well, do the sub: x^2 + (x-1)^2 = 25 or, even without doing the math, you can see that none of the choices satisfies y=x-1 for both points But (d) is also wrong, since the line crosses at (-3,-4) and (4,3) I suspect at least one typo.
September 7, 2016

maths
m = [-5±√(5^2+4*2*20)]/4
September 7, 2016

Math
the time taken by the tortoise is t seconds So, the time used by the hare for running is t-120 seconds The tortoise ran 0.2m farther, so since distance = speed * time, 0.1t = 2(t-120)+0.2 Now just solve for t, and then you can get the distance.
September 7, 2016

algebra
x > 45000
September 7, 2016

math
5/12 + (3/7)(7/12) = 5/12 + 3/12 = 2/3 So, 1/3 of the original amount = 856
September 7, 2016

math
If z = x+yi and a = c+di then zz¯ = (x+yi)(x-yi) = x^2+y^2 a¯z = (c-di)(x+yi) = (cx+dy)+(cy-dx)i az¯ = (c+di)(x-yi) = (cx+dy)+(dx-cy)i so, adding all that up you get x^2+y^2 + 2cx+2dy + b = 0 (x+c)^2 + (y+d)^2 = c^2+d^2-b Looks like a circle to me.
September 7, 2016

Maths Graph
http://www.wolframalpha.com/input/?i=plot+y%3Dx%5E2+for+x+%3D+0..4
September 7, 2016

math
why keep posting the same problem over and over? You know, it just may be that no one is awake in the middle of the night. Surely by now you could have drawn a diagram and seen that if the 2nd elevation was taken at distance x, and the height is h, then h cot35° - h cot55&...
September 7, 2016

math
x+y+z = 95 2x = 4y 2x = 5z 50,25,20
September 7, 2016

Algebra Word promblems
a. correct b. the final salary is less because after the 5% cut ($2500), a 5% raise is less than $2500, since the base salary amount is now less.
September 7, 2016

College Algebra
if it is horizontal, then y never changes. So, what is y at that point?
September 7, 2016

College Algebra
if it is vertical, then x does not change. So, what is x at that point?
September 7, 2016

Physics
1. 60+40 km 2. 100km/1.5hr = 100/1.5 km/hr
September 7, 2016

Math College 115
If a is in years, then you know that when a=0, w=3.8 So, w = 3.8 + ma Now, what is m? It is the change in w divided by the change in a: 37.0/2 = 18.5 w = 3.8 + 18.5a
September 6, 2016

math
well, 400,000,000+30,000,000 = 430,000,000 add the others similarly.
September 6, 2016

Physics
25mi/hr * 1hr/3600s * 1609m/mi = 25*1609/3600 m/s
September 6, 2016

Algebra I need help
google is your friend.
September 6, 2016

Algebra - Reiny is right
Oops. I misread the problem.
September 6, 2016

Algebra
you want w when 900+10w = 500+15w
September 6, 2016

physics
You sure are cagey with the names of your vectors. I'll call them u,v,w. Just draw a diagram. It should be clear that the x- and y-components of vector u are x: -113 cos34° y: 113 sin34° Do the others the same way. For magnitudes, recall that |<x,y>| = √...
September 6, 2016

science
many discussions found via https://www.google.com/#q=electric+field+at+center+of+circular+arc
September 6, 2016

Math Please Help Me
just think about it. How much clay was used? 1 1/2 + 3/4 = 1 2/4 + 3/4 = 1 5/4 = 9/4 lbs Now, if each student uses 1/8 lb, the 1 whole pound is enough for 8 students, right? So 8 * 9/4 = 72/4 = 18 students can be satisfied. Or, since 1/4 lb = 2/8 lb, each 1/4 lb of clay will ...
September 6, 2016

algebra 2
Mary has a 2-hr start, so she's 120 mi ahead at 8 am. Tom hoes 10 mi/hr faster, so how long will it take him to make up the 120 mi?
September 6, 2016

maths
wow - can you make heads or tails of that gibberish? I assume that 22-60 means 22°60'. No idea what "tita" means. Must be "theta". At any rate, since the circumference of the earth is about 40,000 km, the plane flew 8000km = 1/5 of the way around ...
September 6, 2016

Math
just think about it. How much clay was used? 1 1/2 + 3/4 = 1 2/4 + 3/4 = 1 5/4 = 9/4 lbs Now, if each student uses 1/8 lb, the 1 whole pound is enough for 8 students, right? So 8 * 9/4 = 72/4 = 18 students can be satisfied. Or, since 1/4 lb = 2/8 lb, each 1/4 lb of clay will ...
September 6, 2016

Math
rate per hour is #dollars / #hours (1 1/2 + 3/4)/(1/8) or 8 * (3/2 + 3/4) = ?
September 6, 2016

Math
uh, -12/1
September 6, 2016

Algebra1
#1 D is correct #4 B is correct, but the rate of change of f is 2/3, and of g is -3/4 #10 A is correct #1 I agree. Must be a typo. f(1)+g(2) = 4, however #2 C is correct
September 6, 2016

math
start with volume = mass/density find the density of each liquid, and you can figure the volume. Then volume = arae * height You know the area of the liquid cross-section, so once you know the total volume, the height is height = volume/area
September 6, 2016

Technology
seems to me that R T G V F are done with the left index finger
September 6, 2016

Math
Huh? 10+2.5x = 25 2.5x = 15 ...
September 6, 2016

Math
After x years, the height y is y = 10 + 2.5x So, find x when y=25
September 6, 2016

Math
Ths distance of (x,y) from the y-axis is just x. So, √((x-2)^2 + (y-3)^2) = x (x-2)^2 + (y-3)^2 = x^2 x^2-4x+4 + (y-3)^2 = x^2 (y-3)^2 = 4x-4 (y-3)^2 = 4(x-1) as I showed using the properties of parabolas
September 6, 2016

Math
review the definition of a parabola. The standard equation is y^2 = 4px if the focus is at (p,0) and directrix x = -p So, you have to shift your axes giving you (y-3)^2 = 4(x-1) see http://www.wolframalpha.com/input/?i=parabola+(y-3)%5E2+%3D+4(x-1)
September 6, 2016

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