Thursday
September 29, 2016

Posts by Steve

Total # Posts: 44,235

profit and loss
.55*1.05 + .45*1.08 = 1.0635 .45*1.05 + .55*1.08 = 1.0665 so, what is the % change? The amount invested does not matter, since it is all the same.
September 5, 2016

Math
42
September 5, 2016

math
let's just call 4/3 pi = k since it does not depend on r. v(2r)/v(r) = k(2r)^3/kr^3 = 8kr^3/kr^3 = 8
September 5, 2016

Calculus
come on - you did this for 2D figures back in Algebra II: x^2+4x + y^2-2y + z^2-2z = 19 x^2+4x+4 + y^2-2y+1 = z^2-2z+1 = 19+4+1+1 (x+2)^2 + (y-1)^2 + (z-1)^2 = 25
September 4, 2016

Math
since -1 <= sin(u) <= 1 e^x -> +∞ 1/∞ = 0 as x -> +∞ But, oddly enough, this only a one-sided asymptote, since e^-∞ = 0, e^x-2 -> -2 as x -> -∞ And of course, there is the vertical asymptote at x = ln(2) http://www.wolframalpha....
September 4, 2016

calculus
yeah - where f'(x) = 0 f'(x) = -10sinx + 10cos2x now just find where that is zero
September 4, 2016

calculus
Let's take this a step at a time F' = f'(xf(xf(x))) * (xf(xf(x)))' (xf(xf(x)))' = f(xf(x)) + xf'(xf(x)) f'(xf(x)) = f(x) + xf'(x) so: F'(1) = f'(1f(1f(1))) * (f(1f(1)) + f(1)+f'(1)) = f'(f(4)) * (f(4)+f(1)+f'(1)) = f'(6...
September 4, 2016

calculus
clearly there are none.
September 4, 2016

Math
put it where? 2.0*10^-7 / 8.0*10^-9 = (2.0/8.0)*10^(-7 - (-9)) = 0.333 * 10^2 100/3
September 4, 2016

Math
still no ideas of your own? Try google when you have no clue: http://math.stackexchange.com/questions/202679/sum-of-digits-and-product-of-digits-is-equal-3-digit-number
September 4, 2016

Algebra
same as always (1+(2i/n))^2 *(2/n) (1 + 2(2i/n) + (2i/n)^2) * (2/n) 1(2/n) + 2(2i/n)(2/n) + (2i/n)^2(2/n) 2/n + 8i/n^2 + 8i^2/n^3
September 4, 2016

Math Algebra
A is the same distance from (1,3) as B is. You don't need to know that the distance is √29. You just need to subtract the same values from (1,3) as were added to get to (4,-1) (1,3)+(3,-4) = (4,-1) So, you need (1,3)-(3,-4) = (-2,7)
September 4, 2016

algebra
82.4 <= f <= 659.2
September 4, 2016

maths
2(n+12) = 3/2 (2n+12)
September 4, 2016

Math
when you have no clue, try google first: https://answers.yahoo.com/question/index?qid=20090501152219AAtVxte
September 4, 2016

Math
Clearly the T can occur in any of the 3 positions.
September 4, 2016

Math
any of 18 different numbers can show on each roll. So, there are 18*18*18 different sets of 3 events
September 4, 2016

Pre cal
I assume you get this far ok: ... (x-4)(x^2+4) x^3-4x^2+4x-16 evaluate that at x = -1, and you get -1-4-4-16 = -25 That means that if f(x) = a(x^3-4x^2+4x-16) then f(-1) = -25a But, we want f(-1) = -50 so, -25a = -50 a = 2 f(x) = 2(x^3-4x^2+4x-16)
September 4, 2016

Math
wait - we doing heights or lengths? anyway, average = sum/count
September 4, 2016

yuiljk
200/50 + 1
September 4, 2016

Physics
subtract the area of the hole from that of the disc rim; then multiply by the thickness: π(128^2 - 15^2)(0.75) mm^3
September 4, 2016

Math
it will be the same as when it went up.
September 4, 2016

Basic Math
yes, it would.
September 4, 2016

Computer science
If you haven't already written your own routine, google one of your choosing. You should "zero" in on n ≈ 19.2681
September 4, 2016

Physics
work = force * distance the mass does not matter; it just affects how long it will take.
September 4, 2016

MATH
1 * 26^3 * 10^2
September 4, 2016

Algebralgebrad
no, 1+tanx is not the same as 1+tan^2x use your sum-to-product formulas: cosx-cosy = -2 sin(x+y)/2 sin(x-y)/2 sinx+siny = 2 sin(x+y)/2 cos(x-y)/2 so the quotient is just -tan(x-y)/2 the 2nd term is similar recall that (a+b)^3 = (a+b)(a^2-ab+b^2) csc2x = 1/sin2x = 1/(2sinx cosx...
September 4, 2016

Math
since 24 = 6*2^2 any multiple of 6 that does not also have 2 as a factor: 6*1=6 6*3=18 6*5=30 6*7=42 etc.
September 4, 2016

algebra
as with any cone, v = π/12 d^2 h
September 4, 2016

mathematics - algebra
well, tanθ >= 121/915, so ...
September 4, 2016

Pre Calc
http://www.wolframalpha.com/input/?i=-x%5E2%2B9x-8
September 4, 2016

Math
30*4.2 -------- 5/3
September 4, 2016

math help
y = x^2/2 y' = x so, the line through (3,9/2) with slope=3 is y - 9/2 = 3(x-3)
September 4, 2016

Math
5/20 = ...
September 4, 2016

Trignometric
2tan^2(x) + sec^2(x) = 5 - 4tan(x) 2tan^2(x) + 1+tan^2(x) = 5 - 4tan(x) 3tan^2(x) + 4tan(x) - 4 = 0 (tanx+2)(3tanx-2) = 0 Now you know tan(x) cot(a+b) = 6 (cota*cotb-1)/(cota+cotb) = 6 cota = -2, so (-2cotb-1)/(-2+cotb) = 6 -12cotb-6 = -2+cotb -4 = 13cotb cotb = -4/13 or, use ...
September 4, 2016

algebra
how many o's? how many total letters?
September 4, 2016

Math
south: 120 cos46° west: 120 sin46°
September 4, 2016

Algebra
y = k/x 2 = k/6 ...
September 4, 2016

Math
I'll use x for ease of typing each turkey cost x.xx/72 72*x.xx = x67.9x start listing multiples of 72 that end in 9x: 72*11 = 792 72*18 = 1296 72*36 = 2592 Check to see which works out
September 3, 2016

MATH
x+y+z = x*y*z 1+2+3 = 1*2*3 ...
September 3, 2016

physics (Simple harmonic motion)
assuming t is in seconds, I don't see how to get 37.963m http://www.wolframalpha.com/input/?i=0.142sin(2t%2B0.19)+for+0%3C%3Dt%3C%3D210 unless t1 is not zero
September 3, 2016

Calculus
of course, the range is just the same as the range of 2sin(x)+3: [1,5] http://www.wolframalpha.com/input/?i=2sin(sqrt(3x-1))+%2B+3
September 3, 2016

Calculus
no idea. Just take it step by step. domain of √x is x>=0 so, the domain of √(3x-1) is 3x-1 >= 0, or x >= 1/3 the domain of sin(x) is all reals, so the domain of sin(√(3x-1)) is the domain of √(3x-1), or x >= 1/3
September 3, 2016

Calculus
that's a start. Now consider that 4 = 2^2 8 = 2^3 So, log_4(8) = (1/2)log_2(8) = 3/2 log_8(16) = (1/4)log_2(16) = 4/3 (3/2)/(4/3) = 9/8
September 3, 2016

Calculus
e^(1+2lnx) = e^1 * e^2lnx = e * (e^lnx)^2 = e * x^2 That should help some Tsk Tsk, Damon
September 3, 2016

math
The latus rectum's length is 2 times the distance from the focus to the directrix. Now recall the point-to-line distance formula, and you get |3*1-4*1+7|/√(1^2+1^2)
September 3, 2016

Math
as you know, the domain of sin(x) is (-∞,∞) The domain of √x x>=0 so, the domain of √(3x-1) is 3x-1 >= 0, or x >= 1/3 so, can you sort that out?
September 3, 2016

Math
well, geez! How many factors of 16 are there between 6 and 15?
September 3, 2016

math
if the denominator has any factors other than 2 or 5, it will make a repeating decimal.
September 3, 2016

math
you need to plot these values on the number line. You can see that the leftmost point is -3 1/4 and the rightmost is 2 1/3 Thus, the greatest difference is between them: 2 1/3 - (-3 1/4) = 5.583 If "greatest" product means its algebraic value, then any positive ...
September 3, 2016

Math
what a lot of similar problems. I''ll do this one, and maybe you can use it to solve the others. If not, show where you get stuck. 1/3 + 1/4 + 3/8 = 8/24 + 6/24 + 9/24 = 23/24 So, only 1/24 is left, meaning that if he started with x hectares, x/24 = 9 x = 216
September 3, 2016

algebra 1
correct, since both values are rational
September 3, 2016

Maths
if the plane turns south at point P, then if you set AP along the +x axis, then the angle θ=PAB is tanθ = -80/100 θ = -39° That's E39°S or a bearing of 129°
September 3, 2016

maths
Since vertex O is common to both triangles OCD and OAB, you have SAS to show that the two triangles are congruent, making CD and AB congruent.
September 3, 2016

Maths
m + 4(m-20) = 330
September 3, 2016

Math
Hmm. I get x = 2y 3.50x + 5.25y = 1,225.00 Having twice as many dogs as burgers has nothing to do with their prices.
September 3, 2016

Math
Draw a diagram. It should be clear that when the water has depth y ft, the cross-section of water has area y^2/2 ft^2. So, the volume v = 20y^2 dv/dt = 40y dy/dt when y = 6 in = 1/2 ft, 3 = 40(1/2) dy/dt now just solve for fy/dt, the rate the depth is changing. That is, how ...
September 2, 2016

English
#1 is ok, but simply removing the "that" is awkward. Note that it humorously ambiguous: "died suddenly," or "suddenly suprised me"? #2 is syntactically correct, but an unusual usage. I'd not remove the "that" #3 I'd not use "...
September 2, 2016

help please!
consider the parameter t such that when t=0 you are at the first point, and when t=1 you have moved to the 2nd point. For x, the would be x = x1 + (x2-x1)t x = -9 + (2-(-9))t and similarly for y and z.
September 2, 2016

jccc
you gotta work on your copy/paste stuff
September 2, 2016

Electricity and Magnetism
what's the trouble? Just plug into the formula: F = keq1q2/r^2
September 2, 2016

Algebra
just substitute x-3 for each x: h(x-3) = (x-3)^3 + 4(x-3)^2 If you want, expand that into the usual polynomial form.
September 2, 2016

science
trick question carbon filament bulb?
September 2, 2016

science
pooop
September 2, 2016

pre calc!!!
the line through (1,-1,2) is (x-1)/a = (y+1)/b = (z-2)/c and <a,b,c> is the desired direction vector. Note that your parametric equations can be converted to symmetric by eliminating t: (x+7)/-4 = (y+5)/-7 = (z-2)/-4 That should be a large enough clue, no?
September 2, 2016

Algebra
x^3-x^2+x-1 = (x^2+1)(x-1) x^2-1 = (x+1)(x-1) So, the LCM is (x^2+1)(x-1)(x+1) = (x^2+1)(x^2-1) = x^4-1
September 2, 2016

Algebra
just make the substitution: h(a-4) = 2^(a-4)+1 = 2^a/16 + 1 or, if you were careless with parentheses, h(a-4) = 2^(a-4+1) = 2^(a-3) = 2^a/8
September 2, 2016

Algebra
or, -3 * 4*4^(4n) = -12 * 4^(4n) = -12 * 256^n
September 2, 2016

Pre-algebra
1/2 * 2/6
September 2, 2016

Math
much better
September 2, 2016

Math
Nope. |-10| = +10
September 2, 2016

Math
your example is simply volume. Look at the units. You have m^3 + m^2 * m but m^2 * m = m^3 so both terms are volume
September 2, 2016

Math
If the length unit is, say, ft, then length is in ft area is in ft^2 volume is in ft^3 So, see what the power of the unit is to determine the quantity being measured.
September 2, 2016

science ( physics )
The relative speed of A,B and C is x+10 It takes C 1 minute at (x+10)km/hr to cover the 0.5km distance. So, (x+10)(1/60) = 1/2 x = 30 km/hr Or, let the rear car be at point 0, and the front car at 0.5. The rear car is moving in the + direction, and C is moving in the - ...
September 2, 2016

Math Algebra
If the number is xy (digits are x and y), then 10y+x = 10x+y + 36 x+y = 10 Now just find x and y
September 2, 2016

math
recall that sin(180-x) = sin(x) cos(180-x) = -cos(x) Using those two facts, you can replace each angle by its supplement. Now, if you want to get fancy, sin(90+x) = cos(x) cos(90+x) = -sin(x) As Reiny suggested, start by drawing triangles in the "standard position." ...
September 2, 2016

Chemistry
Balance the equation. how many moles in 12.1g H2 ? You'll need twice that many moles of HCl So, how much 27% solution will have that many moles?
September 2, 2016

Algebra 1
5.99x > 5525 + 2.50x
September 1, 2016

algebra
multiply both sides by 4 If two quantities are equal multiplying them by the same value will retain their equality.
September 1, 2016

integrated science
time = distance/speed Plug and chug
September 1, 2016

Calculus
(3^x)(e^x) = (3e)^x recall that d/dx a^x = lna a^x that help?
September 1, 2016

Math
what are all the dots? Do they count for something? so we are just to use a single symbol twice, once for each blank?
September 1, 2016

Algebra
x = 3x+6
September 1, 2016

Math
v = x(3x+2)(2x-4) Now just expand that out
September 1, 2016

physics
s = 1/2 at^2, so 1/2 a * 4.54^2 = 8.1 Now use that to figure how far it goes in the next second. v = a*t s = v*1 + 1/2 a * 1^2
September 1, 2016

science help pls pls
google planetary orbit period You will find lots of explanations, with the formula. I cannot believe that this question was asked of you without providing the formula, either in class or in the text. I also cannot believe that you expect someone to provide it for you.
September 1, 2016

science help pls pls
Just plug these numbers into your formula for orbital periods and subtract.
September 1, 2016

math
first place in standard form: x^2/8 + y^2/3 = 1 Since a^2 = 8 is greater than b^2 = 3, the major axis is horizontal. So, we have a^2 = 8 b^2 = 3 c^2 = a^2-b^2 = 5 Now just read off the info you want: center: (0,0) foci: (±c,0) vertices: (±a,0)
September 1, 2016

Math
consider 8^12 = 8*8*8...*8 12 times 8*9 = 8*8*8...*8 9 times nine of those factors cancel out, leaving 3 in the top, or 8^3 This is why x^m / x^n = x^(m-n) since n of the factors cancel out when reducing the fraction.
September 1, 2016

Discrete Math Proof Exercise
first, you need to show that only even+odd = odd even+even = 2m+2n = 2(m+n) = even odd+odd = 2m+1 + 2n+1 = 2m+2n+2 = even even+odd = 2m + 2n+1 = 2(m+n)+1 is odd so, if 3n^2+5 is odd, 3n^2 is even Since 3 is odd, n^2 must be even, which means that n is even, since odd*odd = (2m...
September 1, 2016

Calculus
Let M = ∫ e^(2x) cos3x dx u = cos3x du = -3sin3x dx dv = e^(2x) dx v = 1/2 e^(2x) M = uv - ∫v du M = 1/2 e^(2x) cos3x + (3/2)∫e^(2x) sin3x dx Now consider ∫e^(2x) sin3x dx u = sin3x du = 3cos3x dx dv = e^(2x) dx v = 1/2 e^(2x) ∫e^(2x) sin3x dx = 1...
September 1, 2016

MATH
3/5 * 3/4 = 9/20 so, if the full amount is x, then 9/20 x = 360 x = 360 * 20/9 5/8 of x is thus (5/8)(360)(20/9) = ?
September 1, 2016

Math
slope = 4, so the point-slope form of a line is y+1 = 4(x+5) massage that into whichever other form you desire
September 1, 2016

Mathematics
since the distance is the same, rate*time is constant. So, you want m minutes where 36m = 15*60
September 1, 2016

algebra,geography
see related questions below.
September 1, 2016

Math asap
and you are wrong. -3 < 2
September 1, 2016

Math asap
see related questions below. I know I've seen this answered at least once for you.
September 1, 2016

Math
still 3, right?
September 1, 2016

Math
15500
September 1, 2016

Geometry
no idea what you are saying: M 6 + 16 + z -1 and 14 ???!?!?!?
September 1, 2016

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