Thursday
July 28, 2016

# Posts by STEVE

Total # Posts: 42,143

Physics
so, how long does it take to fall 0.75 meters? 4.9t^2 = 0.75 Using that time value, the constant horizontal speed is 2.0m/ts = 2.0/t m/s
July 19, 2016

Math
see related questions below. In particular, http://www.jiskha.com/display.cgi?id=1468483941
July 19, 2016

calculus
so, if the divisions are x meters long, we have 4*3 + 6x <= 100 6x <= 88 x <= 44/3 so, 8 <= x <= 44/3
July 19, 2016

math
The curved part (and maybe the base) is just half the surface area of the cone, for which I'm sure you have the formula. The interior which is exposed is just a triangle. Its area is also easy to find.
July 19, 2016

Math
2500(1+r/4)^(4*10) = 6000 (1+r/4)^40 = 2.4 1+r/4 = 1.022128 r/4 = 0.022128 r = 0.0885 = 8.85%
July 19, 2016

Fpb science
mumble mumble
July 18, 2016

Busn math
(3/35) / (9/7) = 3/35 * 7/9 = 3*7 / 35*9 = 3*7 / 5*7*3*3 = 1 / 5*3 = 1/15 or, you could do it (3/35) / (45/35) = 3/45 = 1/15
July 18, 2016

just in case you are having trouble solving exponential equations, eliminate k and you have 2 - 2^(-1-h) = -1 - 2^(-3-h) 3 = 2^(-1-h) - 2^(-3-h) 3 = 2^-h/2 - 2^-h/8 3 = 2^-h (1/2 - 1/8) 3 = 2^-h * 3/8 8 = 2^-h h = -3 Then k = -2, and g(x) = 2^(x+3)-2 See the graph at http://...
July 18, 2016

2^(-1-h)+k = 2 2^(-3-h)+k = -1 solve for h and k Of course many other values for b could have been chosen, but since only two data points were given, something had to be assumed.
July 18, 2016

math
20 + .15x = 35 + .10x
July 18, 2016

Calculus rate of change
A and B are ok. As for C, just showing that f" is a quadratic does not mean that it has two roots. However, if you went ahead and found that it must have two roots because the discriminant is positive, then ok. f is concave up (down) if f" is positive (negative), so ...
July 18, 2016

Calculus @Reiny
huh? height is twice the diameter, not half h = 4r Make that change, Nicole, and redo the steps.
July 18, 2016

physics
50mi/hr = 22.35m/s 22.35m/s / 4.5m/s^2 = 4.97s Now just plug in for distance: s = vt - 1/2 at^2
July 18, 2016

physics
the driver of the truck going 50 mph applies the brakes giving the truck a deceleration of 4.5 m/s^2 how long will it take the truck to come to a complete stop what distance will it cover
July 18, 2016

physics
a sports car can accelerate from 0 to 60 mph in 3.2s what is the acceleration of the car in m/s^2 what distance would it travel at this time
July 18, 2016

Mathematics
If the base has side length s, the total area is a square and four triangles with height 12 (the slant height): s^2 + 4 * (1/2)(12)s = s^2 + 24s Now just solve for s and recall that the volume is 1/3 Bh = 1/2 s^2h where h^2 = 12^2 - (s/2)^2
July 18, 2016

Mathematics
the area is a circular base, a curved side, and a hemisphere: πr^2 + 2πrh + 2/3 πr^3 Now just plug in your numbers.
July 18, 2016

Physics
Luchia's formula will enable you to calculate the distance of each portion of the trip. Then you just need to remember that avg_speed = total_distance/total_time
July 18, 2016

Calculus
been answered. Check previous posts.
July 18, 2016

Physics
120πm/2min = 60π m/min
July 18, 2016

physics
just use the formula KE = 1/2 mv^2 Now plug in your numbers
July 18, 2016

trigonomentry
draw a diagram review your basic trig functions now it is clear that you can find the height h using h cot 18°40' - h cot 26°22' = 50
July 18, 2016

Mathematics
f+2 = 6(s+2) f-3 = 5(s+2) either solve simultaneously, or note that (f+2)/6 = (f-3)/5 Solve for f, and then get s. Kind of a sloppy problem, using s+2 twice.
July 18, 2016

Mathematics
That is equal to (-2b^4y - b^2y^2 + y^2 + y^4 - 2)/(2y) I suspect you mean 1/(4(y+b))+1/(4(y-b))+y/(2(y^2-b^2))-y^3/(y^4-b^4) = (b^2y)/(y^4-b^4) parentheses can make a huge difference. Use them.
July 18, 2016

physics
at = .36 1/2 at^2 = 0.8 a = 0.081 Now you know that F = ma, so you can find F.
July 18, 2016

physics
distance = 3.5 * 2πr displacement = r at all times. After 3.5 revolutions, it is at the opposite end of the diameter where it started.
July 18, 2016

Math
look at the total wins and total games (12+10)/(25+10)
July 18, 2016

MATH - @Writeacher
I guess we'll just keep seeing the question until (a) an answer appears that he likes (b) the assignment is due (c) he posts his own solution
July 18, 2016

MATH
Seems like he'll get 1/4 of them right, and 3/4 of them wrong. So, I'd expect a score of 90*(1/4)*4 + 90*(3/4)(-1/4)
July 18, 2016

science
clearly false, since some acids are corrosive Maybe you meant "not all acids are corrosive" so, what ideas have you on that? what exactly do you mean by corrosive? Is lemon juice corrosive? Vitamin C? Boric acid?
July 18, 2016

calculus
cmon, guy - these are all basically the same. Figure the boundary, decide whether to use shells or discs, and add 'em up. For this one, either will work quite well. cylinders of thickness dx (or dy) have a volume of 2πrh dx discs have a volume of πr^2 dx the ...
July 18, 2016

Word problems using equations
so, the area of the park is 4/5 the total area including the path. If the path has width w, we have 30*24 = 4/5 (30+2w)(24+2w) or, you can say that the area of the path (the whole thing minus the park) is 1/4 the area of the park alone: (30+2w)(24+2w) - 30*24 = 1/4(30*24) ...
July 17, 2016

Math
consider the amount of antifreeze after adding x liters of pure antifreeze: .20*18 + 1.00*x = .40(18+x)
July 17, 2016

Math
20.00 + 0.64*100
July 17, 2016

Math
use the law of cosines. The distance z is found using z^2 = 3^2+4^2 - 2*3*4*cos(135) or, you can figure the x- and y-displacements, then use the distance formula as usual. 3N = (0,3) 4NE = (2.828,2.828) ----------------------- result: (2.828,5.828)
July 17, 2016

math
x = y^2(2-y) So the region in the 1st quadrant is a hump from (0,0) to (0,2) To revolve that around the x-axis it is best to use shells of radius y, thickness dy and height x. So, the total volume is ∫[0,2] 2πy(2y^2-y^3) dy = 16π/5
July 17, 2016

Calculus
Easy way: Consider the water to be concentrated at its center of gravity. How much work to lift that mass 4+3 feet? pi*5^2*8*62.5 lb * 7ft = 274889 ft-lb Calculus way: consider a thin slice of water of thickness dy. Its weight is pi * 5^2 * dy * 62.5 = 4908.734 dy lb Now lift ...
July 17, 2016

Algebra 2
If I read it right, you have (a+3)^2/a - (3/5)/(a^2-9) That is the same as (a+3)^2/a - 3/(5(a^2-9)) place all over a common denominator of 5a(a^2-9). Then you have 5(a+3)^2(a^2-9) - 3a --------------------------- 5a(a^2-9) (5a^4+30a^3-273a-405) / (5a(a^2-9)) which is not ...
July 17, 2016

pre cal
I think you are looking for (5,24). An interesting way to pose the problem.
July 17, 2016

pre cal
shrink horizontally by a factor of 8 stretch vertically by a factor of 8 If you think on it a bit, you should see why. Try using some online grapher to experiment.
July 17, 2016

pre cal
well, f(40) = 3 8f(8x) = 8f(320) Unfortunately, know f(40) tells us nothing about f(320). I think you have left out something.
July 17, 2016

trigonometry
just draw the triangle. The sides are 1,2,√5 Now just read off the trig ratios.
July 17, 2016

Chemistry
First, set up the balanced equation. .025L of .25M HCl has .00625 moles HCl. Now just see how many moles of CO2 are produce for each mole of HCl. Convert the result to grams.
July 17, 2016

Math
Hmmm. Hard to see. The length is 36 and the width is 20. If the height of the box is x, then the base would be 18-x. With the other edge width=20, I don't see how the base can be square.
July 17, 2016

pre cal
g(x) = x^2 extra credit: shifted by how much in each direction?
July 17, 2016

Microsoft Excel
you could always try the different forms and see which works. Just sayin' ...
July 17, 2016

science
well, K = 10^(212/400) = 10^0.53 = 3.388 you can use that
July 17, 2016

MAth
the amplitude is clearly 7.2, so start with y = 7.2 cos(kt) The period is 2*6=12 hours, so k = 2π/12 = π/6 y = 7.2 sin(π/6 t) Now we are stuck. The tide starts at 2m, but is that on the way down, or the way up? And how can that be the trough? The trough is at -7...
July 17, 2016

College Algebra
first of all, it's just an expression, not an equation (no = sign) Since loga + logb = log(a*b) just a x^a * a^b = x^(a+b) log x^n = log(x*x*x*x...)= n*logx assuming logs base 5, but the base does not matter if all the logs are to the same base; the rules apply regardless ...
July 17, 2016

@@
Still, just posting the answer does allow the student to check his results. After all, that's what they really are after, right?
July 17, 2016

mathematics
well, just crank it out: a1=1 a3 = 3a2+2 ... Of course, you do have a problem, since a2 is not defined. Because of a typo.
July 17, 2016

math
check all the powers. Th highest power present for each variable will be in the GCF. (common factor, right?) So, you have 90x^6y^6 18x^4y^4 27x^2y^2 The biggest thing common to all those terms is 9x^2y^2
July 17, 2016

Calculus
that's PI, not pie!! and I have no idea what g.r means. g(r) = 4/3 pi r^3 = 4/3 pi (3t)^3 If you want, you can expand that out. This is just Algebra I, right?
July 16, 2016

Math
I assume the prism has a triangular base and a height of 23. A right triangle with legs of length 12 has sides 12,12,12√2 so, where does the 9 come in? Do you mean a right triangle with legs of length 9 and 12, and thus a hypotenuse of 15? If so, then add up the areas of...
July 16, 2016

maths
that depends. Are the matrices in any way related to the coefficients in the planes' equations?
July 16, 2016

Algebra 2
I would say yes. Have you read your TI-84 manual? Have you tried google? I did, and got https://www.google.com/search?q=TI-84+calculator+recursive+functions&ie=utf-8&oe=utf-8
July 16, 2016

Maths
If there are x chocolates, then we see that x(1 - 1/5 - 1/6) = 38 Now just solve for x
July 16, 2016

math
since there is an even number of values, the median is the average of the two center values: 9, not 11
July 16, 2016

math
well, the numbers are 5,7,11,13 I'm sure you can figure the mean and median.
July 16, 2016

maths
Well, clearly there is no unique solution involving z. Apparently x=3 and y=0 So, any point of the form (3,0,z) will satisfy the equations.
July 16, 2016

math
The machine makes 12000 pieces per day. So, to pay for itself in x days, you need 12000/50*3.00*x = 9000
July 16, 2016

Maths
If the bottle holds b and a pen holds p, then we are told 2b/3 - 7p + 2p = x/4 5b/12 = 5p b = 12p
July 16, 2016

maths - eh?
July 16, 2016

CHECK MY ALGEBRA 2
Hmmm. I don't see any theoretical solution, but after 55 iterations g(x)=4, so that the next time g(x) = 4-2|2-4| = 4-2*2 = 0 g(0) = 4-2|2-0| = 4-2*2 = 0 and it stays zero Maybe roundoff error contributes to this result.
July 16, 2016

Math
well, the length of the base is 2 * 10 * sin15°
July 16, 2016

Math
95 = 5*19
July 16, 2016

Math linear equations
first step: expand to lose the parentheses: 10x-15-9x+21 = 5 Think you can take it from there?
July 15, 2016

Calculus1
Huh? How is this even possible? Anyway, just use the product rule to get a = 1/2 r^2 θ da/dt = 1/2 * 2rθ dr/dt + 1/2 r^2 dθ/dt So, now all you ave to do is find θ when a=20 and r=5 Then plug that in to solve for dθ/dt
July 15, 2016

maths
I'd just find the midpoint of AC or BD, since the diagonals bisect each other.
July 15, 2016

Precalc
July 15, 2016

precalc
In triangle ABC, the angles are A=45 C=60 so, B=75 These are inscribed angles, so if you draw radii from the center O to each vertex, you have AOB = 2*ACB = 120 BOC = 2*BAC = 90 AOC = 2*ABC = 150 Now you have three isosceles triangles. Each triangle with central angle θ ...
July 15, 2016

calc
scalar times vector = vector All the other operations produce vectors, so the result is a vector. vector dot vector produces a scalar, but that's not used here.
July 15, 2016

so, do you have the formula? Can you plug in your numbers?
July 15, 2016

MATH
recall the distance formula: √(4^2 + 5^2)
July 15, 2016

Math
so, since x and y are integers, clearly x=y=0 is a solution If x>0, 2x-1 > x unless x=1, so x=y=1 is a solution For x>1, x/(2x-1) is a fraction. For x<0, x/(2x-1) is always a fraction, so (0,0) and (1,1) are the only integer solutions.
July 15, 2016

Maths
There are 7C5 ways to pick the consonants There are 5C3 ways to pick the vowels Each set of 8 letters can then be rearranged in 8! ways. This is assuming no duplicate letters.
July 15, 2016

Maths
well, there are 6 ways to answer 5 of the 1st 6 correctly (the same as the number of ways to get one of them wrong) That leaves 6 questions, of which 4 can be chosen in 6C4 = 15 ways. Each set of 4 can be answered in 2^4 ways.
July 15, 2016

Maths
no idea what the Cross Method is, but maybe you can fit these solutions into it. After giving away 1/4, there were 3/4 left, so x - x/4 - (1/3)(3x/4) = 120 x - x/4 - x/4 = 120 x/2 = 120 x = 240 Similarly, if Linda started out with \$x, x - x/4 - x/3 - (1/5)(5x/12) = 18.50 x - x...
July 15, 2016

Maths
recall the sides ratios for a 30-60-90 right triangle: 1:√3:2
July 15, 2016

Johnson
distance of elevator from man: 22+2.0t distance of object: 6.5t + 4.9t^2 So, when are they equal?
July 15, 2016

Math
Looks like 11 girls in line
July 15, 2016

Math
The hexagon consists of six equilateral triangles, each with height (the apothem) 4√3 base 8 Now you can easily get the area. To get the base, review the properties of equilateral or 30-60-90 triangles.
July 15, 2016

maths
Draw a diagram. Review your basic trig functions. If the height of the pole is h, then h cot45° + h cot68° = 10
July 15, 2016

Algebra 2
if you mean linear, it has a term of the form ax where a is a constant, and it has no higher powers of x. More generally, it can be written in a variety of forms: ax+by+c=0 ax+by=c y=mx+b y-k = m(x-h) I'm sure your text covers it in some detail.
July 15, 2016

Math
as shown earlier, 3log_2(-x-6)
July 14, 2016

MATH
log_a(3) = log_b(27) log_a(3) = 3log_b(3) log_a(3)/log_b(3) = 3 log_b(a) = 3 b = a^3
July 14, 2016

Math
log_2(x) has asymptote at x=0, so log_2(x+6) has its asymptote at x=-6 But, its domain is x > -6. So, we want log_2(-x-6) at x = -8, we have log_2(8-6) = 1 So, we want y = 3log_2(-x-6)
July 14, 2016

all we know is that 1/25 of the items are red pens. Assuming an integer number of items, that makes C the only reasonable choice.
July 14, 2016

Math
sorry - no pictures here. Surely you can draw a reasonable picture of lines a and b. Let a be the x-axis Then b is the line y=x (45°) Now, line c will be parallel to the y-axis. So, you now have a right triangle with two 45° angles.
July 14, 2016

MATH
or, to avoid introducing a new base, f^-1(x) = log1/3x = -log3x log and exponentiation are inverses, just like + and - * and / square root and square We just don't have any special symbols to denote the operation.
July 14, 2016

mathematics
These would be all the multiples of 24.
July 14, 2016

Math
u.v = 5*3*cosπ/3 = 15 * 1/2 = ?
July 14, 2016

pre cal
just plug in your numbers: cosθ = u•v ----------------------- |u| |u|
July 14, 2016

math
70^2 + 120^2 + 2*70*120 cosθ = 90^2 cosθ = -2/3 θ = 131.8° This makes sense, since if the two forces were separated by an acute angle, the resultant would be greater than either of them. Think of the parallelogram involved.
July 14, 2016

Math
not sure what that is, but it is the graph of log_3(x) reflected through the y-axis shifted right by 3 stretched vertically by a factor of 2 shifted down by 2 Note that log_3(-3x+9) = log_3(3) + log_3(3-x) = 1 + log_3(3-x) This cancels the scale factor on the x-axis by ...
July 14, 2016

Chemistry
well, 12g C + 32g O2 → 44g CO2 ?? If all 18g of C were used, there would be only 66g CO2. Am I missing something here?
July 14, 2016

algebra
it will take t hours, where 1.039^t = 2
July 14, 2016

Math
you want y(0) = 5, so log3(k^2)-1 = 5 log3(k^2) = 6 k^2 = 3^6 k = 27
July 14, 2016

Science
write the balanced equation convert grams to moles find the limiting reagent see how many moles of it will be used see how many moles of H2O will result convert back to grams
July 14, 2016

Maths
The factors of 6262 are 1x6262 2x3131 31x202 62x101 The first two are out, since there's no room for the blue border and red interior. So now, check the others and pick the one which allows for more red tiles. 29x200 60x99
July 14, 2016