Friday
September 30, 2016

Posts by Steve

Total # Posts: 44,265

Algebra
Treat it as you always do fractions. Multiply by the denominator to clear the fraction: -54/x = -6 -54 = -6x Now it's a cinch, right? |x| is the "size" of x, regardless of whether it is positive or negative. It is defined as |x| = x if x >= 0 |x| = -x if x <...
September 23, 2016

Algebra
shift left: x -> x+4 stretch: y -> 3y shift up: y ->y+5 g(x) = 3(x+4)^2+5
September 23, 2016

GEOMETRY
The change in coordinates from A(-6, -3) to B(3, 1) is (3-(-6),1-(-3)) = (9,4) 1/3 of the difference is thus (3,4/3) (-6,-3) + (3,4/3) = (-3,-5/3) (-3,-5/3) + (3,4/3) = (0,-1/3) (0,-1/3) + (3,4/3) = (3,1) The first two points divide AB into 3 equal parts.
September 23, 2016

science
adage: opposites attract
September 23, 2016

maths
One, two! One, two! And through and through The vorpal blade went snicker-snack! He left it dead, and with its head He went galumphing back. "And, has thou slain the Jabberwock? Come to my arms, my beamish boy! O frabjous day! Callooh! Callay!' He chortled in his joy...
September 23, 2016

Math
well, 5+7 = ?
September 23, 2016

math
50 <= c <= 150
September 23, 2016

math
I'll just use x for ease of typing (note the use of parentheses to make things clear!) 1/(1+sinx) + 1/(1-sinx) =((1-sinx)+(1+sinx))/((1+sinx)(1-sinx)) = 2/(1-sin^2(x)) = 2/cos^2(x) = 2sec^2(x) By far the most useful trig identity is sin^2(x) + cos^2(x) = 1 It pops up in ...
September 23, 2016

Math
well, if they are not equal, one must be less than the other.
September 23, 2016

Calculus
if you don't know that the slope of the curve is given by the derivative, I suggest more study, or google will provide many discussions. Assuming that you believe that the derivative of a function gives the slope of the curve at any point, then you just have to remember ...
September 23, 2016

Operating System
once you get past the sloppy English, you might provide a little more information, doncha think?
September 23, 2016

12
well, the numbers are 2k 2k+2 2k+4 2k+6 multiply them and you have 2^4(k(k+1)(k+2)(k+3)) Now, two of those numbers must be even, so the product is divisible by 2^6 In addition, the product of 3 consecutive numbers is divisible by 6, so 2^7*3 = 384 divides
September 23, 2016

math
original fraction: (x-3)/x (x-3+4)/(x+4) = 3/4
September 23, 2016

value
each hour, 1/2 - 1/3 = 1/6 of the tank is filled. That should help some...
September 23, 2016

Maths, science
maximum volume is achieved when the box is a cube. The area of the box is c^2, so each face has area c^2/6 That means the side has length c/√6. v = (c/√6)^3 = c^3/(6√6) Hmmm. Better double-check my math.
September 23, 2016

Chemistry
figure the moles each mole fills 22.4L at stp
September 23, 2016

dosage calculations
looks ok to me
September 23, 2016

Calculus
f'(a) = R means f(a) = Ra + C But, if f is odd, C=0 So, f(-a) = -f(a) = -Ra
September 23, 2016

Algebra
reflected: y = |-x| stretched: y = 1.5|-x| shifted: y = 1.5|-x| - 4 However, since |-x| = |x| the reflection has no effect.
September 22, 2016

Math
48,136.47 / 7
September 22, 2016

Math
40 + 32.60*8
September 22, 2016

geometry incomplete
no information on the relative placements of the points.
September 22, 2016

Msth
300+300
September 22, 2016

taxation
no, it isn't.
September 22, 2016

Math
1in : 8ft = 1in : 96in = 1:96
September 22, 2016

Algebra
oops. Forgot to multiply the 4
September 22, 2016

Math
you have (almost) listed them in order of distance from zero, but smallest means farthest to the left. And even then, 2.4 is closer than 2 1/2
September 22, 2016

Algebra
by the time you get to algebra, you should know about fractions ... -2x+1/3y=4 -2(-3) + 1/3 y = 4 6 + y/3 = 4 y/3 = -2 y = -6
September 22, 2016

Math (Plz Help ASAP)
-7 -7(10*60)
September 22, 2016

math
the difference is 25 km/hr so, 25*12 km
September 22, 2016

Math
sloppy use of the = signs, there.
September 22, 2016

Algebra
|n-0| < 6
September 22, 2016

Math
well, y = 6x-12 plug and chug 6(-3)-12 = -30 ...
September 22, 2016

PHYSICS
if the acceleration is in the same direction as the velocity, the object speeds up. Otherwise, the acceleration opposes the velocity, so it slows down.
September 22, 2016

Math
since ln8 = 3ln2 is just a number, you have ∫(2x^2 ln⁡8)dx = ∫2x^2*3ln2 dx = 6ln2∫x^2 dx = 2ln2 x^3 = ln4 x^3 + C Maybe you had a typo, I'm guessing... If so, recall how to do integration by parts: ∫x lnx dx u = lnx du = 1/x dx dv = x dx v = 1...
September 22, 2016

Physical Science/ Chemistry
reading down the column, they become more reactive.
September 22, 2016

Math
so, what two numbers add to 9 and one is twice the other? Come on - there aren't that many pairs that add to 9.
September 22, 2016

Math
x = amt at 4% x-2000 = amt at 5% Now just compare the interest: .05(x-2000) = .75*.04x
September 22, 2016

MATH
#1A is correct, but it is not scientific notation for the value. #2B is also correct, but not S.N. #3 is 0.593 x 10^4 But, to make it S.N., you need to have 5.93 x 10^3 #4 5.2 x 10^8 / 25 = 0.208 x 10^8 That is 2.08x10^7 Looks like you need some serious review on how to move ...
September 22, 2016

Physics
v(t) = Vo + at = 85 - 13t It stops when v=0.
September 22, 2016

Algebra
stop guessing and start working 1/r * s = s/r, so p=s/r + d p-d = s/r Now what do you think?
September 22, 2016

maths
depends on the value of y. But, since 12y-12 = 12(y-1) it is certainly not prime.
September 22, 2016

Math
2.3(4.5-9.6)+3.1 = 2.3(-5.1)+3.1 = -11.73+3.1 = -8.63 you are correct. If your input on the calculator is as accurate as your typing here, it is no surprise that is sometimes wrong...
September 22, 2016

Algebra
the slope of the perpendicular line is -1/7 So, knowing that the line through (h,k) with slope m is y-k = m(x-h) what do you think?
September 22, 2016

Computing
I think you mean virtual memory. If so, just google it for many discussions.
September 22, 2016

Math
incorrect writing as a ratio is just one way of expressing rational numbers. Terminating or repeating decimals is another way.
September 22, 2016

Math
sorry - you wanted the bearing of Q from X. Just subtract 180°.
September 22, 2016

Math
since Q to P is 140°, P to Q is 320° P to X is 315°, so angle QPX is 5° using the law of cosines, |QX|^2 = 36^2 + 55^2 - 2*36*55*cos5° = 376.1 So, |QX| = 19.39 km 55^2 = 19.39^2 + 36^2 - 2*19.39*36*cosQ So, Q = 165.7° The bearing of X from Q is thus 140...
September 22, 2016

Physics
it stops going up when v=0. So, since v = 15 - 9.8t v=0 at t=1.53 So, at t=2.5 it is coming back down: http://www.wolframalpha.com/input/?i=15t+-+4.9t%5E2
September 22, 2016

Physics
t is 2.5 Vi is 15 m/s up a = -9.8 m/s^2 up (or, 9.8 m/s^2 down) d = Vi * t + a/2 t^2 = 15*2.5 - 4.9 * 2.5^2 = 6.875 m Vf is Vi + at = 15 - 9.8 t^2 (though it does not matter for this question)
September 22, 2016

Math
x = 2 A = {2}
September 22, 2016

Math - eh?
{x: x 3x=6} ?? Do you mean {x: 3x=6} ?? Then you ask Does A? Does A what? However, you are correct in saying that {2} is not 2
September 22, 2016

Computer science
https://en.wikipedia.org/wiki/Virtual_memory
September 22, 2016

math
(72+84+90)/6 + 90/2 = 86
September 22, 2016

math
also check out the way the coefficients are sums of subsets of the roots: http://mathforum.org/library/drmath/view/61024.html
September 22, 2016

Mathematics
list a few how far apart is each from its neighbor?
September 22, 2016

math
think of the factors of 18 which two differ by 3?
September 22, 2016

Algebra
x = x/3 + 8 + 52
September 22, 2016

Math
(1 hr 54 sec) * 7 And yet, I suspect you meant 1 hr 54 min.
September 22, 2016

Algebra
900/(300+250) hours later
September 22, 2016

Math
6:8:15 * 7/5 = 42/5 : 56/5 : 21
September 22, 2016

calculus
x^2+y^2 = 10^2 so, when x=6, y=8 2x dx/dt + 2y dy/dt = 0 Now just plug in your values to find dx/dt
September 22, 2016

math
14250 * 1.02^3
September 22, 2016

United States History
thank you
September 22, 2016

United States History
How is this map different from a typical map of the United States? I couldn't get the map to paste here but it is of the Eastern United States with all the states names crossed out and Irish names put in. circa 1900's I think it was during the potato famine when Irish ...
September 22, 2016

Math
2P = 3*1000
September 22, 2016

Math
Since x:y = 7:9, y = 9x/7 (9/7)x = x+10
September 22, 2016

Algebra
d+t = 48 t+8 = 3(d+8) Now just solve for d and t.
September 22, 2016

Math
well, does it?
September 22, 2016

Math
well does it?
September 22, 2016

Geometry
just take each point and see whether the rule transforms it to the desired point. For example, (x,y+1) transforms (2,4) -> (2,5) Then see which rule takes all 3 points where you want them.
September 22, 2016

Math
Use the first pair to get the ratio 60/3 = 20 So, for each pair, the 2nd value should be 20 times the 1st value.
September 21, 2016

AP physics
their combined speed is 1560 km/hr time = distance/speed, so ...
September 21, 2016

Math
You asked: Determine the number of seats in a bus for each value of r. yet you did not provide any values of r. So, I picked one: 0 Now you pick some others and evaluate 5 + 4xr for each one. I like to help with answers, but don't make me come up with the questions, too.
September 21, 2016

Math
0: 5 ...
September 21, 2016

algebra
so far so good: 17/4x = 23/(x+6) now cross-multiply (shorthand for saying multiply by the LCD): 17(x+6) = 23(4x) 17x + 102 = 92x 102 = 75x x = 102/75 = 34/25
September 21, 2016

Math algebra
hint: think "difference of two squares"
September 21, 2016

MATH HELP
1C w/o the typo no ideas on the others?
September 21, 2016

Math
just write their areas as a ratio 24:15 or 8:5
September 21, 2016

algebra
all ok
September 21, 2016

Math (Geometry)
statement: if A then B converse: if B then A
September 21, 2016

Math
a/(1-r) = 100 ar = 24 divide and you have 1/(r(1-r)) = 100/24 r = 2/5 or 3/5 a = 60 or 40
September 21, 2016

Math
first step: list the possible combinations of coins: 4q, 0d, 1n ... 0q, 0d, 21n Then note how many cannot change $1.00
September 21, 2016

Physics
a = -45m/s / 9s = -5m/s^2 s = 45t - 5/2 t^2
September 21, 2016

Math
time to review your basic trig functions. The height h is found by h/100 = tan50°
September 21, 2016

MATHEMATICS
after t hours, the fraction left is (1/2)^(t/9) So, after 3 hours, there is (1/2)^(3/9) = .7937 of the original amount left.
September 21, 2016

Math
time = distance/speed, so (400/(150/20)-400/(100/12.5))(100/12.5) = 26.66m
September 21, 2016

Math
(400/(150/20)-400/(100/12.5))(100/12.5) = 26.66m
September 21, 2016

MATH
after t hours, the amount left is 2 * (1/2)^(t/5)
September 21, 2016

jay
nope. And where are your divide symbols? P/2 = l+w now go from there.
September 21, 2016

Calculus
I assume you want k and m so that g(x) is continuous? Just to make things easier, recall that e^(ln u) = u so, e^(ln(2x+3)) = 2x+3 If so, then you want the endpoints to match: (k(-2)^2)+m = 2(-2)+3 k(3)-m = 2(3)+3 or, 4k+m = -1 3k-m = 9 I guess you can handle that, yeah? As ...
September 21, 2016

math
20-4-4-4-4-4 = 0
September 21, 2016

Physics
8.0 m/s^2 * 1km/1000m * (3600s/hr)^2 = 103680 km/hr^2 after h hours, the distances must be the same: 91.0h = 52.0h + 51840h^2 h = 0.000752315 hours = 2.7 seconds Or, you may want to convert km/hr to m/s, but the answer is the same. To get the distance, just plug it into either...
September 21, 2016

math
well, 2.5 = root(6.25) now just order the squares.
September 21, 2016

Math
2m^2+m-2m = 2m^2-m = m(2m-1) I suspect a typo, as this does not fit well with the grouping techniques.
September 21, 2016

Math
I get 4502 counted using bash: for i in `seq 1 11521` ; do echo $i ; done | tr -c -d '3' | wc -c
September 21, 2016

biomechanics
how long does it take for v to drop to zero? v(t) = 14.27 - 1.67t using that t, the distance moved is s(t) = 14.27t - 0.835t^2
September 21, 2016

Physics
or, more directly, recalling that the range is R = v^2/g sin2θ just solve for v in v^2/9.8 * sin62° = 8.3
September 21, 2016

Math
you manage to use + and x, but can't manage / ? 18+9x(5+4)/3-5 18+9x9/3-5 18+81/3-5 18+27-5 ... or 18+9x(5+4)/3-5 18+9x(9/3)-5 18+9x3-5 18+27-5 ...
September 21, 2016

trigonomentry
not sure what you mean by a "series" of cos, but if you recall your binomial expansions, (a+b)^4 = a^4+4a^3b+a^2b^2+4ab^3+b^4 and then let a=1 and b=cos^2(x), you have sin^8(x) = (sin^2(x))^4 = (1-cos^2(x))^4 = 1 - 4cos^2(x) + 6cos^4(x) - 4cos^6(x) + cos^8(x)
September 21, 2016

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