Friday
July 3, 2015

Posts by STEVE


Total # Posts: 32,081

Math
the line through the two given points is y-4 = -7(x-1) Now use that to find the desired values.
May 10, 2015

maths
25^2 = 625 so, figure 26^2, and subtract 630 from that. or, find √630 = 25.099 so, since 25^2 < 630 and 26^2 > 630 as above...
May 10, 2015

maths
well, 1000^2 = 1,000,000, which is the smallest 7-digit number. 10 times that will be 8 digits. √10 = 3.1622, so 3162^2 = 9,998,244 3163^2 = 10,004,569
May 10, 2015

Maths - eh?
apparently the sum of all the shaded areas is less than the shaded area of the triangle. I don't see how that can be.
May 10, 2015

algebra
that will be when 1.05^t = 2 Now add that t to 2000
May 10, 2015

Algebraic Geometry
If the 2nd is x, then we have (x-5) + x + 2(x-5) = 33 x = 12 Now figure the legs.
May 10, 2015

Math
A+B+C = 26 (B+3)+B+(2B-1) = 26 Now you find B, and thus A and C.
May 10, 2015

matrices
well, B^2 = 0 0 1 1 0 0 0 1 0 Now do it again.
May 10, 2015

Math too hard please help
n: C=10n+26 ------------------ 27: 10(27)+36 = 270+36 = 306 and so on with the other values
May 10, 2015

trig
find the angle between the pole and the wire using the law of sines: 35/sin30 = 25/sinθ Now use the law of sines again to find x, since you can now figure the angle opposite x.
May 10, 2015

Trig
or, having found B, you can use the law of cosines: x^2 = 35.4^2 + 10.2^2 - 2(35.4)(10.2)cosB
May 10, 2015

Trig
If the ladder makes an angle A with the ground and B with the embankment, then using the law of sines, 35.4/sin 117.5 = 10.2/sinB = x/sinA Now you can find B, and A = 180-(117.5+B) and you can find x.
May 10, 2015

binomial expansion
since the powers add up to 12, that would be the 10th term: 12C9 (√2)^9y^3 = 12C3 (16√2)y^3 = 3520√2 y^3
May 9, 2015

binomial theorem
That would be 22C19 a^3 b^19 = 22C3 a^3 b^19 = 1540a^3b^19
May 9, 2015

trig
note that h cot38° - h cot75° = 65
May 9, 2015

Pre-Calculus
cos x cot^2 x= cos x cos x cot^2 x - cos x = 0 cos x (cot^2 x - 1) = 0 cosx = 0 cotx = ±1 Now you can just find x, right?
May 9, 2015

math
4 pink out of 14 total, so P(pink) = 4/14 = 2/7
May 9, 2015

Common Core Math II A-CR
recall that the height h is given by h(t) = 128t - 16t^2 That's just your good old friend, the parabola. Find its vertex -- that is the maximum height.
May 9, 2015

precalculus
suppose the terms were -3,-2,-1,0,... would that be hard tto figure out? Well, it's the same here: (t-2)-(t-3) = 1 (t-1)-(t-2) = 1 The common ratios for the 2nd one are found by dividing each term by the previous one: 1,-3/2,2,-5/2 (-3/2)/(1) = -3/2 2/(-3/2) = -4/3 (-5/2...
May 9, 2015

precalculus
see related questions below
May 9, 2015

Trig
all you need here is the perpendicular distance from Nancy's plane to a N-S line. If that distance is x, then x/400 = sin 23° x = 156.29 you are correct. Nasty how they sneak in unrelated problems, eh?
May 9, 2015

algebra
1.22x = 3200000 x = 2622950.82
May 9, 2015

math
5x+7 = 7x-21
May 9, 2015

math
well, A+B=180, so solve for x. Also, A+D = 180
May 9, 2015

math
2*15/√3
May 9, 2015

math
the two angles are equal, so just set them equal and solve for x Then figure MRQ
May 9, 2015

Math
one statement is by definition independent.
May 9, 2015

algebra
If x at 40%, the rest (20-x) is 85%. So, .40x + .85(20-x) = .60(20)
May 9, 2015

Maths
2560/58.0 = x/(9.50*8.75)
May 9, 2015

maths
clearly a = √7 r = √3 An = √7*√3^(n-1)
May 9, 2015

english
1st step is learning to write it. As in Can you help me in my debate topic, 'Knowing English well is equal to having a college degree'?
May 9, 2015

physics
consider that T^2 = kr^3 That means that T^2/r^3 is constant T^2/r^3 = (2T)^2/(xr)^3 = 4T^2/x^3r^3 So, 4/x^3 = 1, and x = ∛4 That is, our small planet's orbital radius is ∛4 times earth's.
May 9, 2015

maths
d = (32-11)/(12-5) = 3 a = 11-4*3 = -1 now you can fill in the rest.
May 9, 2015

math
nth from front is a + (n-1)d nth from l is l - (n-1)d their sum is a+l Not sure what you meant by "a l"
May 9, 2015

precalculus
the coefficients are 1,3,3,1 so you have 1(2x)^3(-3y)^0 + 3(2x)^2(-3y)^1 + 3(2x)^1(-3y)^2 + 1(2x)^0(-3y)^3 = 8x^3 - 36x^2y + 54xy^2 - 27y^3
May 9, 2015

extreme math help please
change in x: 2 change in y: 3 y = 3/2 x - 5
May 9, 2015

college precalculus
check for common difference or ratio: #1: d = 1 #2: r = 2/3 #3: differences: -5/2, +7/2, -9/2, ... ratios: -3/2, +4/3, -5/4, ... neither d nor r is constant, so the sequence is not AP or GP
May 9, 2015

algebra
y grows by 5 when x grows by 1. So, since 6-1=5, when x=6, y=4+5*5 = 29 or, using the point-slope form, y-4 = 5(6-1)
May 8, 2015

Calculus
(a) ok (b) ok (c) g" = (x^2-4x+16)/(x-2)^2 Since g" is never negative, g is never concave down (d)correct, but since you know g(3)=4, y-4 = -9(x-3) (e) since the graph is always concave up, any tangent lines must lie below the graph. Doodle around some, and you will ...
May 8, 2015

Physics
distance = speed * time, so that wold be 3.00*10^5 km/s * 1.28s = 3.84*10^5 km
May 8, 2015

trigonometry
well, geez. I gave you the information: h(cot35+cot25) = 1650 Now just solve for h!
May 8, 2015

trigonometry
Drop the altitude from C to P, with height h AP = h cot35 PB = h cot25 AP+PB = 1650
May 8, 2015

calculus
rather than just sit around waiting, why not actually try it yourself? 1/[x^2(1+x^2)] = 1/x^2 - 1/(1+x^2) and those are both easy, right?
May 8, 2015

math
no ideas? Recall that L{y} = F(s) L{y'} = s F(s) - f(0) L{y"} = s^2 F(s) - s f(0) - f'(0) then just collect terms, solve for s, and do L^-1{s}
May 8, 2015

math
5/8 x = 13 x = 13 * 8/5 Strange, since 13*8 is not a multiple of 5.
May 8, 2015

algebra
Are the clubs mutually exclusive?
May 8, 2015

Physics
A heat engine is 20% efficient. If it loses 800 J to the cooling system and exhaust during each cycle, the work done by the engine is: 200 J 1000 J 800 J 20 J
May 8, 2015

extreme math help please
note that y decreases by 1 when x increases by 2. So, start with y = -1/2 x But, -1/2 (2) = -1, and y(2) = 1. So, y = -1/2 x + 2
May 8, 2015

Physics
How many kg of ice needs to be added to 1.31 kg of water at 64.9°C to cool the water to 14.9°C when the Latent heat of ice = 80 kcal/kg?
May 8, 2015

Calculus, derivatives
x^2+2r√y = xy If y is constant, it's just like any other dumber, so 2x dx/dr + 2√y = y dx/dr dx/dr (2x-y) = -2√y dx/dr = 2√y / (y-2x)
May 8, 2015

math
a quadratic function involves x^2 So, (C) is a quadratic. Surely you could have discovered that information (a) in your text (b) via google
May 8, 2015

math
when x increases by 2, y increases by 3. So, start with y = 3/2 x But y(0) would be 0, and the table says it is -5. So, y = 3/2 x - 5
May 8, 2015

Calculus
y = 5x√(121-x^2) This is an odd function, so algebraically, the area is zero -- equal areas above and below the x-axis. By symmetry, the geometric area is a = 2∫[0,11] 5x√(121-x^2) dx If you let u = 121-x^2, du = -2x dx, so a = 2∫[121,0] -5/2 √u ...
May 8, 2015

Calc 2
well, consider that 11n just gets bigger and bigger without bound. csc(x) has an asymptote at x = π That is, csc(x) -> ∞ as x -> π So, csc^1(x) -> π as x -> ∞ Or, in the case of our sequence, lim {csc^(-1) 11n} = π n->∞
May 8, 2015

math
.05x = 95
May 8, 2015

Math
Assuming a sinusoidal function, we have the area is (letting x=0 in September) a(x) = 7.5 cos(pi/6 x) + 10.5 we want a(x) > 15. In other words, cos(pi/6 x) > 0.6 -1.77 < x < 1.77 so, using symmetry, in one complete period (a year), there are 3.54 months with more ...
May 8, 2015

maths
Let v = victor v+24 = lahai so, adding them up, you have v + v+24 = 60
May 8, 2015

STS
since s=w+3, w=s-3 3/2 = s/(s-3)
May 8, 2015

Math
correct
May 8, 2015

STS
.10(40) + 1.00(x) = .20(40+x)
May 8, 2015

STS
.12x = 69
May 8, 2015

mathematics
that would be totalpoints/totalstudents: (35*80 + 15*70)/50
May 8, 2015

Geometric Series
a = 5(-1/6)^5 Note that (-1/6)^(5k) = ((-1/6)^5)^k, so r = (-1/6)^5 S = a/(1-r) = (5(-1/6)^5)/(1-(-1/6)^5) = -5/7777
May 7, 2015

math
um, how about 16*3.5 ?
May 7, 2015

Math
If I get past the font gibberish, I sense that you want to prove that 4 sinθ sin(60-θ) sin(60θ) = sin 3θ That isn't so, so try reposting using sin^3 θ for cube of sinθ if that's what you mean.
May 7, 2015

Calculus
the curve is concave down. So, (c)
May 7, 2015

trigonometry
what, forgotten your algebra I, now that you're taking trig? -3sin(t)=15cos(t)sin(t) 15cos(t)sin(t) + 3sin(t) = 0 3sin(t)(5cos(t)+1) = 0 sin(t) = 0 or cos(t) = -1/5 So, find the 4 values of t which do that. 8cos^2(t)=3-2cos(t) 8cos^2(t)+2cos(t)-3 = 0 (4cos(t)+3)(2cos(t)-1...
May 7, 2015

Math
The horizontal parabola y^2 = 4px has directrix p units from the vertex. So, since our directrix is 3 units from the vertex, we start with y^2 = 12x But, that's with a vertex of (0,0). So, our parabola is (y-1)^2 = 12(x+2) But, that opens to the right. Our vertex is to the...
May 7, 2015

Calc/Precalc
just do the same stuff: xy = cot(xy) y + xy' = -csc^2(xy) (y + xy') y'(x + xcsc^2(xy)) = -ycsc^2(xy)-y xy' (1+csc^2(xy)) = -y(1+csc^2(xy)) xy' = -y y' = -y/x The other is just a simple chain rule. y = cos(u), so y' = -sin(u) u'
May 7, 2015

Poly
42
May 7, 2015

math
4 of each length...
May 7, 2015

Math
can't happen. The angles must add up to 360.
May 7, 2015

Math
hint: r = 3
May 7, 2015

Math
That would of course be 6C2 (3x)^4 (-y)^2 = 15(81x^4)(y^2) = 1215x^4y^2
May 7, 2015

Trig
no, no. Draw your triangles: if cos(s) = 1/5, then sin(s) = √24/5 = 2√6/5 if sin(t) = 3/5, then cos(t) = 4/5 sin(s+t) = (2√6/5)(4/5) + (1/5)(3/5) = (8√6+3)/25 and similarly for sin(s-t)
May 7, 2015

maths
you want km/L. So, use what you have: (44km)/(11/4 L) = 44km * 4/11L = 16 km/L
May 7, 2015

Calculus
that would be ∫[0,2] f(x) dx ------------------- 2-0
May 7, 2015

Algebra
15+12x+40 = 127
May 7, 2015

matha
250500 * 1/5 * 2/5 = ?
May 7, 2015

Calculus
V = ∫[-1,1] π(e^x)^2 dx or V = ∫[0,1/e] 2π(1/e)(1-(-1)) dy + ∫[1/e,e] 2π(y)(1-lny) dy
May 7, 2015

maths
3/4 of 4L = 3L 1 - 3/4 = 1/4
May 7, 2015

Calculus
we can check using shells. V = ∫[0,1] 2πrh dy where r = 1-y and h = y-y^3 V = 2π∫[0,1] (1-y)(y-y^3) dy = 2π∫[0,1] y^4-y^3-y^2+y dy = 2π(1/5 y^5 - 1/4 y^4 - 1/3 y^3 + 1/2 y^2) [0,1] = 2π(1/5 - 1/4 - 1/3 + 1/2) = 2π(7/60) = 7π...
May 7, 2015

Calculus
or, using shells, you can do V = ∫[0,9] 2πrh dy where r = y and h = 3-x = 2π∫[0,9] y(3-√y) dy = 2π(3/2 y^2 - 2/5 y^(5/2)) [0,9] = 2π(3/2 * 81 - 2/5 * 243) = 2π(243/10) = 243π/5
May 7, 2015

Math
x + 1/ x - 1 + x^2 -1 / x + 1 x+(1/x)-1+x^2-(1/x)+1 x-1+x^2+1 x+x^2 However, assuming the usual sloppiness with parentheses, I suspect you meant (x+1)/(x-1) + (x^2-1)/(x+1) (x+1)/(x-1) + (x-1)(x+1)/(x+1) (x+1)/(x-1) + (x-1) (x+1)/(x-1) + (x-1)^2/(x-1) (x+1 + (x-1)^2)/(x-1) (x^...
May 7, 2015

Help plz on Calc
Think of the shells as nested cylinders, starting 1 unit away from the y-axis, and extending to the end of the ellipse: V = ∫[1,3] 2πrh dx where r=x and h=y V = 2π∫[1,3] x(2√(1-x^2/9)) dx = 2π/3 ∫[1,3] 2x√(9-x^2) dx = 2π/3 (32/...
May 6, 2015

intermediate algebra
if the radiator already contains pure antifreeze, how would adding more antifreeze change anything?
May 6, 2015

intermediate algebra
better read what you posted . . .
May 6, 2015

Algebra
a = 100 r = -1/20 An = ar^(n-1) Sn = a (1-r^n)/(1-r) A4 = 100(-1/10)^3 = 100(-1/1000) = -1/10 S4 = 100(1-(-1/10)^4)/(1 - (-1/10)) = 100(9999/10000)/(11/10) = 909/10
May 6, 2015

calculus
so, find a table of integrals and look it up. You will probably just find some power reduction formulas, such as ∫ x^n sinx dx = -x^n cosx + n∫ x^(n-1) cosx dx You can see that you will have to use integration by parts 4 times to get rid of all the x^n terms. So, ...
May 6, 2015

precalculus
since the vertices are on the y-axis, we will have y^2/a^2 - x^2/b^2 = 1 the slope of the asymptotes is b/a, so y^2 - x^2/4 = 1 but that has vertices at (0,+/-1) so y^2/4 - x^2/16 = 1 To verify, see http://www.wolframalpha.com/input/?i=hyperbola+y%5E2%2F4+-+x%5E2%2F16+%3D+1
May 6, 2015

geometry
tanθ = 1/11
May 6, 2015

math
all are correct, with the following notes: #1 has a typo. The 3rd y value should be zero Why say "1 over 3" when real mathematical notation (1/3) is so much better?
May 6, 2015

chemisrty
The molar mass of Fe(OH)3 is 106.87 g/mol. How many moles of H2SO4 are needed to react completely with 5.419 g of Fe(OH)3?
May 6, 2015

math
well, on the RS, csc^2 - sec^2 = (cos^2-sin^2)/(sin^2 cos^2) That should help...
May 6, 2015

mathematics - eh?
what does "sin alpha 9" mean?
May 6, 2015

Math
that's cylindrical cup sheesh. the area of the circular base, is just the area of a circle. pi r^2 the curved surface is just the circumference times the height: 2pi r h Now just plug in your values for r and h
May 6, 2015

Math
well, just offhand, I'd say that's 80% of 64. Or, .80 * 64 = ? Hmmm. Since 64 is not a multiple of 5, how could 80% (4/5) do it?
May 6, 2015

GEOMETRY
Oh come on. Do you have a triangle? parallel lines? intersecting lines? Geez, just describe the arrangement of the points and lines, fer cryin out loud! What is the relationship between MO and NA? Perpendicular? Parallel? Pretend I can't see the diagram. Tell me what to do...
May 6, 2015

GEOMETRY
you'd better describe the figure. Some of your copy/paste is garbled, and we have no idea of the relative locations of the points.
May 6, 2015

math
y changes by +1 when x changes by 1. So, the slope is +1/1 = 1.
May 6, 2015

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