Saturday
December 3, 2016

Posts by steve

Total # Posts: 46,781

maths - incomplete
Not known, since (a) you did not say how many pictures there are (b) you did not say how many pictures are on a page (that has pictures) Try reading what you write before posting.
November 7, 2016

Math
can't be done 62% = 62/100 = 0.62 Not a whole number
November 7, 2016

Chemistry
Can you check my answers? Thanks!!!! What would happen to the volume-to-temperature ratio if: 1. One student failed to replenish the boiling water in the boiling-water bath as the flask was being heated. At the end of the 6 min of heating, the boiling water in the bath was ...
November 7, 2016

Calculas-Differentiation
you know that f'(2) = 0 2ax+b = 0 at (2,8) 4a+b = 0 4a+2b = 8 So, b=8 a = -2 y = -2x^2 + 8x see http://www.wolframalpha.com/input/?i=-2x%5E2+%2B+8x or, without calculus, you know that -b/2a = 2 since the vertex is there. so b = -4a y(2) = 8, so 4a + (-4a)(2) = 8 a = -2 so ...
November 7, 2016

Algebra
20% less, or 580*.80
November 7, 2016

maths
You keep posting this same stupid problem without enough description to pin it down. AB can be almost any length, depending on the shape of the figure. If the rectangle is ABCD, and the triangle has base CD and vertex E, then still all we know is that AB + 2*AD + 2*DE = 46 Of ...
November 7, 2016

Geometry
do you mean the two sides opposite each of the angles U and V? Normally a side opposite an angle (such as X) is labeled with the lower-case letter of the angle (x) , or the letters of the two vertices at the ends of the side. That would be sides u (VW) and v (UW)
November 7, 2016

business math
well, the amount of interest per day was 278/280 So, the percent interest per day was (278/280)/3800 = .0002613 = 0.02613% Now multiply that by how many days in a year ...
November 7, 2016

arithmetic
hmmm. what is the difference between 7 and 12? How did you get it? Do the same for these two numbers.
November 7, 2016

Maths
just list 'em for MSQ and then replace each letter with the corresponding one from UVW.
November 7, 2016

dynmic
what step by step? The same equation (h = vt - g/2 t^2) applies to both balls, so just set them equal: 30t-4.9t^2 = 50(t-3) - 4.9(t-3)^2 http://www.wolframalpha.com/input/?i=30t-4.9t%5E2+%3D+50(t-3)+-+4.9(t-3)%5E2
November 6, 2016

Math
LB: (360-7)/2 NO: (25-8)/2 Even without doing the actual math, just seeing that much of LB is quite high should make things clear. Now, neither of those averages is -2, but surely NO has a better chance of being near that. What that means is that while the mean of high and low...
November 6, 2016

Math
Sometimes it helps to use the intercept form of a line. 5x - 12y = 60 x/12 + y/-5 = 1 The intercepts are 12 and -5, you you have a 5-12-13 right triangle.
November 6, 2016

Math
It depreciated to 1/2 its value in 6 years. (1/2)^(1/6) = 0.89089 So, the depreciation rate is .1091 = 10.91% per year
November 6, 2016

Calculus
Wll, there is much unsaid here, but if we assume the pyramid has a square base of side length x, and height y, then V = 1/3 x^2 y = 2.2 y = 6.6/x^2 Now, the area of tent is x^2 for the floor 2x?(x^2+4y^2) for the sides So, you want to minimize the cost c = x^2 + 1.4*2x?(x^2+4y...
November 6, 2016

statistics
since the variable of interest is distance, it is continuous. Unless you are measuring the number of shots, which is discrete, but might be involved in a different sampling scheme...
November 6, 2016

math
h/(82*7*60) = sin 13°
November 6, 2016

maths
rectangles and triangles come in many shapes. You need to pin down some of the properties a little more exactly. Is the base of the triangle the same as one of the sides of the rectangle? Anyway, label the sides of your figure, and add them up. They must sum to 46. Can't ...
November 6, 2016

Math
p=3s s=j+4 p+20 = 2(j+20) Now just solve for p.
November 6, 2016

Trigonometry
If we label things as T: town P: plane A: airport Then in triangle TPA, using the law of cosines, 29^2 = 34^2+48^2 - 2*34*48*cosP P = 36.6° Now you can figure out the heading. (the same as the bearing of A from P)
November 6, 2016

science
electron clouds, rather than actual orbits.
November 6, 2016

math algebra
x at 3.5%, so the rest (3000-x) at 2.5% Now just add up the interest: .035x + .025(3000-x) = 190
November 6, 2016

Calc 1
I assume that you mean C(m) = (-.41m^2 + 6.7m - 44)/.7m As you recall from Algebra I, that is C(m) = (1/.7)(-.41m + 6.7 - 44/m) so, C'(m) = (1/.7) (-.41 + 44/m^2) = (1/.7)(44-.41m^2)/m^2 Since the denominator is always positive, C'(m)=0 when 44-.41m^2 = 0 m^2 = 44/.41 ...
November 6, 2016

Calc 1
no. e^(-3x) is never zero, so where is (1-3x)=0? x = 1/3 so, a = (1/3)e^(-3*1/3) = 1/(3e) don't forget your Algebra I now that you're in Calculus!
November 6, 2016

Calc 1
a = xy = xe^(-3x) da/dx = (1-3x)e^(-3x) so, where is da/dx = 0?
November 6, 2016

College Alg
40000(1+.08)^5 Good luck with that!
November 6, 2016

College Alg
P(1+.09/4)^(4*18) = 41000
November 6, 2016

maths
42
November 6, 2016

Algrebra readiness
Not so. Think about your answer. 9+12=21 Those cannot be the sides of a triangle. The 9 and 12 sides would have to lie completely flat on top of the 21 side. The third side must be less than 9+12. In fact, if the 3rd sides is x, 12-9 < x < 12+9
November 6, 2016

PreCalc Oops
oops - that's a+4d=6 But I'm sure you caught that...
November 6, 2016

PreCalc
just crank it out using the formulas you already know: a+5d = 6 12/2 (2a+11d) = 45
November 6, 2016

Calculus
d^2s/dt^2 = -4cos(2t)+sec^3(t)+sec(t)tan^2(t) now just plug and chug.
November 6, 2016

Algebra readiness
?25 + -9 = 5-9 = -14 integer
November 6, 2016

algebra
I thought it was 13/84, but that does not work. However, 1/6 + 1/7 = 13/42
November 6, 2016

Maths
Using discs (washers), they stack up with thickness dy or dx, as needed. (a) v = ?[0,2] ?(R^2-r^2) dy where R=4 and r=x=y^2 = ?[0,2] ?(16-y^4) dy = 128?/5 (b) v = ?[0,4] ?(R^2-r^2) dx where R=2 and r=2-y=2-?x v = ?[0,4] ?(4-(2-?x)^2) dx = 40?/3 Or, you can use nested cylinders...
November 6, 2016

Math, Precalc
can't see your diagram, but consider the vectors representing the diagonals. If it's a unit cube, they might be joining (0,0,0) and (1,1,1) = <1,1,1> (1,1,0) and (0,0,1) = <-1,-1,1> (1,0,0) and (0,1,1) = <-1,1,1> ... Now just take the dot product of ...
November 6, 2016

Calculus
Actually, since f(x)=0 at all those points, we can use Rolle's Theorem, which is just a special case of the MVT were f(a) = f(b) on the interval [a,b]. Both theorems state that f'(c) exists with c in (a,b) such that the tangent is horizontal. That is, f'(c)=0, ...
November 6, 2016

Math-Trigo
Just draw your 5-12-13 triangle in standard position cot(90-A) = tan(A) = y/x = -12/5
November 6, 2016

physic
if 30°, then just find t when the height is zero: 30*sin30° t - 4.9t^2 = 0
November 6, 2016

math
Oops. adding the equations eliminates y. 7x = 28 ...
November 6, 2016

math
You meant: I can't; help me. 5x-2y = 14 2x+2y = 14 ------------- add the two equations 4y = 28 I expect that you can handle it from here, eh?
November 6, 2016

Math
6+2x=24
November 6, 2016

math
recall that a regular hexagon has sides equal to the circle's radius.
November 6, 2016

calculus - PS
#1 is not quite so amazing if you recognize that if a = tan(u) x = tan(v) y = arctan(tan(u+v)) = u+v y' = v' ...
November 6, 2016

calculus
recall that if y = arctan(u) y' = 1/(1+u^2) u' y=arctan(a+x/1-ax) y = 1/(1+((a+x)/(1-ax))^2) * (1+a^2)/(1-ax)^2 = ... amazing! y=(e^x-e^-x)/(e^x+e^-x) = tanh(x) ...
November 6, 2016

Science
brain
November 6, 2016

math
(50/4)*(4-1) = 37.5
November 6, 2016

Physics
step 1: what is the volume of the cube of ice? step 2: find out how much water is produced when the ice melts. It will decrease in volume by some percentage.
November 5, 2016

Pre-Calculus
It's the length of u in the direction of the unit vector v/|v|, so u • v/|v|
November 5, 2016

Algebra 2
log(30,8) = log8/log30 Since the base on the right does not matter, we can use base 10, giving us 3log2/(log2+log3+log5) = 3c/(c+b+a)
November 5, 2016

physics
volume(cm^3) = mass(g)/density(g/cm^3) so plug in your numbers. I assume you can find the side of a cube, given its volume. (By the way, the length is cm, not cm^3!)
November 5, 2016

algebra
PV=kT, so PV/T=k is constant. o, you need V such that 30V/330 = 35*20/350 V/11 = 2 V = 22
November 5, 2016

chem.
If there are x moles of Kr, then there are 2x moles of Ar. Since the number of moles has increased by a factor of 1.47/1.26, 2x+x+.3 = 3x(1.47/1.26) x = 0.6 So, there were originally 1.2 moles of Ar, making the final amount 1.5 moles.
November 5, 2016

Advanced Physics
Since you don't give any time values, there's no way to figure displacements. Also, the vector does not move; some object does. Also, your explanation is odd. How do you turn southeast? You can turn 30 degrees clockwise, which is toward the SE. Or do you mean that the ...
November 5, 2016

Pre cal
recall that vertical asymptotes occur when the denominator is zero and the numerator is not. Removable discontinuities are where the fraction is 0/0 Horizontal asymptotes are what happens when x gets huge. f(x) = (x-3)(x+2) -------------- x^2 (x-4) get it now? If not, where do...
November 5, 2016

Math
If he had d dimes, then he had 3d nickels. So, add up the value of each group of coins: 10d + 5(3d) = 100
November 5, 2016

math
you can play around with Z table stuff here: http://davidmlane.com/hyperstat/z_table.html
November 5, 2016

algebra
x = kF x/F is constant. You want F such that 9/F = 10/8
November 5, 2016

Algebra
or, assuming the usual carelessness with parentheses, (4r+12)/8 = (5r-20)/5 r/2 + 3/2 = r - 4 r = 11
November 5, 2016

math
24*2+36 = 84 kg flour 50 kg sugar So, now you can figure how many packets of each were made, and thus how many got both.
November 5, 2016

math- Trigonometry
Look. If cos(x) = 0.8641, you use your cos^-1 button to get x. cos^-1(.8641) = 30.22° sin 30.22° = 0.5033 So, since they gave you the answer in two different ways, as well as a sanity check to see why it makes sense, what is your work, which produces something else? If...
November 5, 2016

sir-reiny-steve help
assuming all were shot somewhere, (42+43+32) - (5+8+6) + x = 100 Review your Venn diagram material to see why.
November 5, 2016

Math gemetry
apparently, not to study geometry with a social worker!
November 5, 2016

Math
#1 ok #2 you have solved 3n = -12 #3 You have solved b/9 = 19 #4 You have solved y-1.8 = 3.18 Did you not check your answers to see whether they actually worked?
November 5, 2016

Math 062
5642/403 * 3
November 5, 2016

Advance function
just think back to your Algebra II. Terms of a GP have a common ratio, so tanx/sinx = sin2x/tanx 1/cosx = = 2sinx*cosx * cosx/sinx ...
November 5, 2016

Math
3 - 1 of each color
November 5, 2016

Math
suppose there were 40 cows = 160 feet so, you would need 32/2 = 16 fewer cows: 24. The 32 feet would be made up with 16 hens.
November 5, 2016

Adv function
I think you misplaced a minus sign. Fix it and think "difference of squares"
November 5, 2016

Calculus - huh
Not what I expected, but quite true. The equilateral triangle has area 4?3 < 8
November 5, 2016

Calculus
do some setup and I'm sure you will find that the problem is solved by a regular n-gon regardless of the number of sides. Just define the third side in terms of the included angle.
November 5, 2016

Maths
15.01 15.001 15.0001 17.999 17.99 17.9 I'm sure you can find many more
November 5, 2016

math
sin(a) cannot exceed 1. Fix your typo and repost.
November 5, 2016

algebra
.03x + .04y = 170 .04x + .03y = 180 now crank it out.
November 5, 2016

mathematics
Any point will have its x-coordinate reversed in sign.
November 5, 2016

math
get numbers add to get sum avg = sum/3 update max and min as the list is read in
November 5, 2016

time speed and distance
your turn to provide some ideas. We've done several of these for you by now.
November 5, 2016

Maths
v = pi r^2 h = pi r^2 r ... 2pi r (r+h) = 2pi r(r+h) = 1 ...
November 5, 2016

Maths
each 1cm layer of water has a volume of 30^2 * 1 = 900 cm^3 So, what's the total volume of the fish? Divide that by 900cm^3 to find how much the water level rises.
November 5, 2016

math
well, their combined rate is 720/4 = 180 mi/hr
November 5, 2016

science
convert to moles see how much H2SO4 remains after being neutralized by twice that many moles of KOH. Convert that back to moles/L
November 4, 2016

Calculus Reimann Sum
so, how did you do it? If the interval is [-2,3] then each interval has length 1, so I fail to see how you got the fraction.
November 4, 2016

algebra 1
5x-2 passes through (8,38) So, you need to subtract 40 so it goes through (8,-2)
November 4, 2016

Calculus
Note the sum. You have a2-a1 + a3-a2 + a4-a3 + ... + a21-a20 = a21-a1 = 2^21 - 2^1 There's really no reason to write the sum as you did. Since you know a_i explicitly, it would be better just to say 20 ? 2^(i+1)-2^i i=1
November 4, 2016

Calculus - Special sum formulas
see your other post. Repeating it does no one any good. Don't forget your Algebra I now that you're taking Calculus!
November 4, 2016

Calculus - Special sum formulas
Huh? You have the answer. Just simplify if you want: n(n^2-37)/3
November 4, 2016

Pre-algebra
no. all whole numbers are rational (fractions with denominator=1, as in 2/1, 4/1, etc.) There are lots of numbers that are not rational (irrational), like ?, ?3, ?5, etc. They cannot be expressed as the ratio of two integers.
November 4, 2016

Calculus
a = 24t+4 v = 12t^2+4t+11 s = 4t^3+2t^2+11t+15 so, s(9) = ?
November 4, 2016

Calculus - Differential Equations
oh come on. 0+C = -4/6 C = -2/3 -4/u = t - 4/3 u = -4/(t - 4/3) = 12/(4-3t)
November 4, 2016

Calculus - Falling Body Problem
it is well known that the equations are s(t) = 3000+75t-16t^2 v(t) = 75-32t So plug and chug Extra credit: derive those equations.
November 4, 2016

Calculus - Differential Equations
so, crank it out: 4 du = u^2 dt 4/u^2 du = dt -4/u = t+C now plug in (0,6) to get C.
November 4, 2016

Tricky Math Question
However, if you look at the graph for y = x^x the limit near zero is 1. limit x^x log(limit) = x*logx = logx/(1/x) use l'Hospital's rule: = (1/x) / (-1/x^2) = -x log(limit)=0, so limit=1
November 4, 2016

Pre-Algebra
right Although we're not really using the associative property. That would state that (2.25 • 23) • 4 = 2.25 • (23 • 4) All you did was evaluate the expression inside the parentheses and replace it with an equal value.
November 4, 2016

Math
well, the floor is 10x16 tiles in size, so ...
November 4, 2016

ss
well, surely you know that (a) N-S directions are latitude (b) N.A. is west of England...
November 4, 2016

physics
If ? is the angle upstream, then you have sin? = 2.5/7.3
November 4, 2016

science
y = tan? x - g/(2 (v cos?)^2) x^2 so plug in your numbers and solve for v when y(10) = 2
November 4, 2016

MATHS
which area? lateral, total, circular base? I'll assume the base. Volume = base_area * height
November 4, 2016

Physics
(v^2 sin2?)/g = v^2 sin^2?/g 2sin? cos? = sin^2? 2cos? = sin? tan? = 2
November 4, 2016

Physics
result of downward and sideways motion.
November 4, 2016

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