Saturday
April 30, 2016

Posts by Steve

Total # Posts: 40,032

math
well, 5*3 = 15, so ...
February 28, 2016

Calculus
surely as a calculus student, you can determine C and k: at t=0, C/(1+C) = 1/200 C = 1/199 Since you say daily volume, I assume t is in days, so at t=28, (1/199)e^28k/(1+(1/199)e^28k) = 1/100 k ≈ 0.025 = 1/40 p(t) = 1/199 e^(t/40)/(1+1/199 e^(t/40)) increasing most ...
February 28, 2016

Math
dy/dx = (dy/ds)/(dx/ds) = (-24s^2)/(18s) = -4s/3 naturally, dy/dx=0 at s = 0 see the graph http://www.wolframalpha.com/input/?i=plot+x+%3D+9s^2+-+1,++y+%3D+1+-+8s^3
February 28, 2016

Math
2.58x = 92.96
February 28, 2016

geometry
Draw a diagram. If the intersection points subtend an angle of θ, then the area of overlap is 2*(1/2)r^2(θ-sinθ) so, you have 6.17^2 (θ-sinθ) = 42.7 θ = 2 The distance between centers is then 2rcos(θ/2) = 2*6.17*cos(1) = 6.67
February 28, 2016

Algebra
If the smaller is x, the larger is x+10. So, we have 2(x+10)-x = 14
February 28, 2016

Maths
T11-T3 = 8d = (-7)-9 = -16 so, d = -2 Now you can find a, and then write the 1st 5 terms. Or, knowing d=-2, and T3=9, you can work from both sides of T3: 13 11 9 7 5
February 28, 2016

Grade 11 Functions
what you are doing wrong is ignoring the cotangent function. If you check your diagram, you will see that the height h is found using h cot17° - h cot21° = 60 h = 90.1 m
February 28, 2016

Chemistry
N2 + 3H2 = 2NH3 ever heard of google?
February 28, 2016

math
planes fly on headings, not bearings. Man, those two headings are almost the same. The distance will be very nearly 200+350. However, using the law of cosines, the distance z is z^2 = 200^2 + 350^2 - 2*200*350*cos178°
February 28, 2016

Math.
the discount is 30-22.50 = 7.50 The % discount is 7.50/30 = .25 = 25%
February 28, 2016

maths
apparently you want a = 16πr^2 can't happen But, if you meant a = 16π then you have 16π = πr^2 r^2 = 16 r = 4
February 28, 2016

Computer
LET S = (N/2)*(2*A + (N-1)*D) you don't need much of a program or flowchart to evaluate a simple expression...
February 28, 2016

Grammar
#1. Better would be He would neither show me his papers, nor tell me who he is. #2. I don't possess anything else. #3 is ok, but "every" is singular: Every man in the street stood where he was.
February 28, 2016

@Reiny - mea culpa
Ouch - I must be going Blind!
February 27, 2016

precal
diameter = 11, not radius
February 27, 2016

Calculus Pre Test Monday Part 3
s(t) = 180-5t^2 (a) avg velocity is total distance/total time. s(2) = 180-5*4 = 160 160m/2s = 80 m/s v(t) = ds/dt = -10t v(4) = -40 180-5t^2 = 0 t = 6 That is, at t=6, the height is zero -- it hit the ground. Now you just plug 6 into v(t)
February 27, 2016

Maths
y = 2cos(2x)cos(14x) use the product rule: y' = 2(-sin(2x))(2)cos(14x) + 2cos(2x)(-sin(14x))(14) and you can factor out some numbers there. The verb is differentiate, not derive. It would work the same way in general: y = 2[cos1/2(f1 - f2)x][cos1/2(f1 + f2)x] y' = 2(-...
February 27, 2016

Math
Umm, I guess that would be (2358-99)/3 right?
February 27, 2016

Math
9 1-digit numbers 90 2-digit numbers so, there were (2358-99)/3 3-digit numbers
February 27, 2016

Algebra
(x+2)(x-2) = (x+2)^2 + (x-2)^2 - 16 Not sure what a "double product" is, so if I got it wrong, just fix it and go on.
February 27, 2016

Algebra
since distance = speed*time, (s+2.5)(2) = (s-2.5)(6) find s, then you can get the distance.
February 27, 2016

math
(a) 1/6^3 (b) ditto (c) (a)+(b)
February 27, 2016

geometry
Draw a diagram. If the circle has radius r, and the girls stand a distance 2x apart, and the rope subtends an angle 2θ, we have x^2 + (r-4.5)^2 = r^2 x/(r-4.5) = sinθ r sin2θ = 20 If you wade through that, you will get x ≈ 17
February 27, 2016

algebra 1
.04x + .05(10000-x) = .04x + 500 - .05x = 500 - .01x
February 27, 2016

Math
Right. I misread you r text. But, wolfram's answer looks the same to me, if you allow that ∫ du/u = ln|u|
February 27, 2016

Math
1 - 12/(x-2) + 17/(x-3) You lost the 1. Other than that, it's ok.
February 27, 2016

math
collect all the coefficients ad powers: (-6x^6)(-6x^2x^6) = (-6x^6)(-6x^8) = (-6)(x^6)(-6)(x^8) = (-6)(-6)(x^6)(x^8) = 36x^14
February 27, 2016

algebra 1
well, -3 = 3*7 + b solve for b, and that is the y-intercept.
February 27, 2016

physics
2400W/240V = 10A
February 27, 2016

college physics
I'm assuming the given vector is <25,-16> So, you want a vector pointing in the +x direction, where y=0. So, <-18,+16> will do the trick. Adding the two gives <7,0>
February 27, 2016

Math Word Problem
If there are x at 4 pts and y at 5 pts, we have x+y=52 4x+5y=22 Sorry. 52 courses must add up to a lot more than 22 credits. Fix the numbers and solve the equations.
February 26, 2016

Math
.25A + .20(10-A) = .22(10)
February 26, 2016

math
each 1" cube holds eight 1/2" cubes, not 2/
February 26, 2016

Math
no. Each plant weighs 2.6 lbs so, 2 plants weigh twice as much 3 plants weight 3 times as much ... x plants weigh 2.6x And tell your dad, Dan Quayle, that tomato has no "e".
February 26, 2016

khan
F = Gm^2/d^2 You say the force is 6.67*10^-11N and then ask for the force. You have the equation. Fix your text and solve it.
February 26, 2016

Calculus
the answer will depend on the number of trapezoids. A handy calculator is found at the URL below. You can compare your steps with those found there http://www.emathhelp.net/calculators/calculus-2/trapezoidal-rule-calculator/ There are others as well.
February 26, 2016

Math
vertical asymptotes where the denominator is zero. To find horizontal asymptotes, find y when x gets really huge. Remember that 1/∞ = 0
February 26, 2016

Calculus
The radius of the water's surface at a depth of h is r = 11/48 h So, the volume v is v = 1/3 πr^2 h = π/3 (11/48)^2 h^3 so, dv/dt = 121π/2304 h^2 dh/dt So, when h=400, dv/dt = (121π/2304)(400)^2(16) = 422370 cm^3/min That is the rate at which v is ...
February 26, 2016

Math 11
just plug in your numbers: 3.4 = 2π√(L/9.8) Just solve for L
February 26, 2016

Precal
heavens! How did you get that? y = 1/(x-4) + 3 x-4=0 when x=4 So, there is a vertical asymptote at x=4 Now, what happens when x->∞? 1/(x-4) -> 1/∞ -> 0 So, y=0+3 = 3 is a horizontal asymptote See the graph at http://www.wolframalpha.com/input/?i=1%2F%28x-4...
February 26, 2016

Precal
vertical asymptotes where the denominator is zero. To find horizontal asymptotes, find y when x gets really huge. Remember that 1/∞ = 0 ∞-4 = ∞
February 26, 2016

math
see related questions below on how to set it up to find the cost of operating the truck
February 26, 2016

algebra
the axis is x = -b/2a max height reach when x = -b/2a solve for x when h=3. There will be two answers: one when going up, and one when going back down.
February 26, 2016

Math
c = 420h where h is the number of hours riding
February 26, 2016

Science HELP PLS
surely you can google the two planets and get a wealth of information
February 26, 2016

MATH PLEASE
if the price is p, you want 1250000p = 780000 + 1250000*19.85 + 650000
February 26, 2016

Math Algebra
1250000p = 780000 + 19.85*125000 + 650000 p = $20.99
February 26, 2016

Probability! Check please!
7C4 = 7*6*5*4/4! = 35 There are 28 2-topping sundaes
February 26, 2016

Geometry
C = ((2+8)/2,(3+1)/2) = (5,2) slope of CD = (2-8)/(1-3) = 3 since CD=√10, it is the hypotenuse of a triangle with legs 3 and 1. Since the slope is 3, that means that the x-leg=1, and the y-leg=3. So, it could be C+(1,3) = (6,5) or C-(1,3) = (4,-1)
February 26, 2016

math/algebra
The general term is Tn = n(n-1)-5 So, for n=1,2,3,4,5,... replace each n by the given value. That gives T1 = 1(0)-5 = -5 T2 = 2(1)-5 = -3 T3 = 3(2)-5 = 1 and so on
February 26, 2016

MATH
There is no equation, since there is no = sign. It's just an expression. The first line in WORK does not match the original expression. From that point on, however, things look good.
February 26, 2016

Math
3.14 * 4^2
February 26, 2016

Math
multiply by 7^2
February 26, 2016

calculus
Draw a diagram. It is clear that when the batter has gone x feet, his distance z from 2nd base is z^2 = (90-x)^2 + 90^2 so, 2z dz/dt = 2(x-90) dx/dt so, figure z when x=45 and plug in the numbers The distance from 3rd base is very similar.
February 26, 2016

algebra or algebra1
Assuming you mean √(2^3/(-7)^2) = (2/7) √2
February 26, 2016

Geometry
If the equal sides are s and the base is b, 2s+b = 50 (b/2)^2 + 5^2 = s^2 For QRST, TQS is an isosceles right triangle, so QS = 8√2 QRS is isosceles, with vertex angle 60°, so QR=RS=√8 = 2√2. So, QRS is equilateral. So diagonal TR is the sum of the two ...
February 26, 2016

Algebra
if you mean exactly 90, then 83+92+x = 3*90 If you mean at least 90, then all scores from x to 100 will work.
February 26, 2016

MATH
review the definitions of the figures. It will become clear.
February 26, 2016

Math
(20-15)/20 = 5/20 = 25%
February 26, 2016

Math
check to see whether a^2+b^2 = c^2 It helps to know the sizes of common integer-sided right triangles: 3-4-5, 5-12-13, 8-15-17
February 26, 2016

co-ordinate geometry maths
Find the area of DEF in the usual way, as, for example http://www.mathopenref.com/coordtrianglearea.html Since DEF is 1/2 the size of ABC, the area of ABC is 4 times the area of DEF.
February 25, 2016

math
just add 6 inches to the radius
February 25, 2016

A.P
is that 3P - 1/6 or (3P-1)/6 ? Plug in P=1 for the first term T1 Recall that the sum is n/2 (T1 + Tn) now plug and chug
February 25, 2016

math
56 cubes of 1" sides will fit inside the 56in^3 block. volumes scale as the linear factor cubed, so 8*56 1/2" blocks will fit. Each 1" cube holds 8 1/2" cubelets.
February 25, 2016

math
3^5 = 243 So, all powers of 3 that are multiples of 5 also ends in 3. 7^5 ends in 7 11^n ends in 1 for any n 8^5 ends in 8
February 25, 2016

math
the draws are independent. what is the chance that no heart is drawn? (3/4)^3
February 25, 2016

math
6/10 * 8/10
February 25, 2016

Precalc
by definition, log_b(b^z) = z So, log_4(4^3x) = 3x 6 log_6(36) = 6 log_6(6^2) = 6*2 = 12 3 log_2(1/2) = 3 log_2(2^-1)) = 3*-1 = -3 1/4 log_4(16) = 1/4 log_4(4^2) = 1/4 * 2 = 1/2
February 25, 2016

Math
3(.06) = 0.18 miles
February 25, 2016

Math
h/20 = 1.5/0.1
February 25, 2016

Science
google is your friend
February 25, 2016

Mathematics
if z = x^2y-y^2-2x ∂z/∂x = 2xy-2 ∂z/∂y = x^2-2y If they are both zero (the stationary point), then xy=1, so y=1/x x^2-2/x = 0 x^3-2=0 x = ∛2 so, y=1/∛2
February 25, 2016

Math
yep.
February 25, 2016

Math
well is it true that 5 = 8+6 ??
February 25, 2016

Math
p: two triangles are congruent q: their areas are equal p => q
February 25, 2016

statistics please help!
since the card is replaced each time, the chance on each draw is 1/4. So, ...
February 25, 2016

Help Math
correct. The first roll is either even or odd. So, the chance that the 2nd roll is odd (or even) is 1/2
February 25, 2016

Math
(x - 1/a)(x+a) = 0
February 25, 2016

Math
7x+3x = 80 solve for x, and the groups are 7x and 3x
February 25, 2016

MATH
12-10 = 2, not 8 For a quick check on your answers , just type in your expression at wolframalpha.com. See http://www.wolframalpha.com/input/?i=-7-3[-80%2F|12-10|]
February 25, 2016

Math
84+96+85 + x = 4*90
February 25, 2016

Algebra
x^3+y^3 = (x+y)(x^2-xy+y^2) 6(x^2-xy+y^2) = 144 x^2-xy+y^2 = 24 y = 6-x, so x^2-x(6-x)+(6-x)^2 = 24 x^2-6x+x^2+x^2-12x+36 = 24 3x^2-18x+12 = 0 3(x^2-6x+4) = 0 Look familiar?
February 25, 2016

Algebra A
You can always tell a lazy clod -- they copy the instructions for submitting the answer. To do this, just substitute one equation into the other: x+y=6 means y = 6-x So, x^2+y^2 = 28 x^2 + (6-x)^2 = 28 x^2 + x^2-12x+36 = 28 2x^2 - 12x + 8 = 0 2(x^2-6x+4) = 0 Now it's easy...
February 25, 2016

Math
19m*12m*2.7m = 615.6 m^3 km are length, not volume. And why would one be interested in km^3 for a dinky swimming pool? At any rate, just recall that 1km = 1000m
February 25, 2016

Stats please help
1/6 * (5/6)^3
February 25, 2016

Stats please help
1/2 on each toss, right?
February 25, 2016

Stats please help
5/6 on each toss, right?
February 25, 2016

Stats please help
well, what's the probability of getting no sixes at all?
February 25, 2016

Mathematics
just remember the product rule and the chain rule x^2y = y^2 + 2x 2xy + x^2yy' = 2yy' + 2 y'(x^2y-2y) = 2-2xy y' = 2(1-xy) ------------- y(x^2-2)
February 25, 2016

Math
duh there was a typo and you missed it. Always check the answers you find.
February 25, 2016

Alg 2 function operations
well, just substitute in the values: f(x)+g(x) = (-5x-4)+(6x-7) can you get it now?
February 25, 2016

math
g = c-10 c = l-5 g = 5
February 25, 2016

Geometry
since the medians are all inside the triangle, surely (A) Try drawing some. A triangle can only have three acute angles, or one obtuse angles. google triangle medians and see lots of images. You will see that no matter what the shape of the triangle, the medians must always ...
February 25, 2016

Math
I've found that m<4 usually means "the measure of angle 4". But, with no diagram to refer to, it's not possible to relate the angles and their measures.
February 25, 2016

Maths
so, if the acute angles are 6x and 13x, that means that 6x+13x=90 x = 90/19 and the other two angles are 540/19 and 1170/19 or, we might have 90=13x, so one of the other angles is 6x, and we have the third angle z as 90 + (6/13)(90) + z = 180 z = 630/13 Why cannot 90 be 6x?
February 25, 2016

Science
try putting your question in the box at google. Or, shucks, read your class text. Or, learn how to read the periodic table.
February 25, 2016

Math (Pre-Cal)
all you need is to find t such that 1.12^t = 2
February 25, 2016

science
Not enough information. The direction of one of the vectors is not enough. We know that the other is perpendicular to it, and that the diagonal of the rectangle is 100. But that just means that the rectangle is rotated by 60° It could have sides of 60 and 80, or 12 and 8&#...
February 25, 2016

Chemistry
However, the desired reaction is probably 2N2H4 + N2O4 = 3N2 + 4H2O adjust the moles ratio accordingly
February 25, 2016

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