Friday
February 12, 2016

Posts by STEVE

Total # Posts: 37,610

math
If the cost is x, .93x = 31 x = 33.33 Profit at Rs 35 = 1.167 = 3.5%
December 20, 2015

Maths
Use matrices or determinants. How far do you get?
December 20, 2015

maths
If you consider that LCM(2,3)=6 a = x^4/y^3 b = y^2/2x You want terms of the form a^2b^3 or a^4b^6, ... Since we have a 10th power expansion, the exponents must add to 10, so we are looking for a^4b^6. That is, the 5th term: C(10,4) a^4 b^6 = 210 x^16/y^12 y^12/64x^6 = (105/32...
December 20, 2015

Maths
I'm sorry -- I mussed have missed the memo. What was the question?
December 20, 2015

Partial fraction
Since both factors in the denominator are irreducible quadratics, each numerator will have the form of (Ax+B) I get (1/10)(x-3)/(x^2+1) + (1/10)(7x+5)/(3x^2+4x+5)
December 20, 2015

Maths
you solve an equation. I don' see no steeking equation. All you have is an expression. What do you want to do with it?
December 20, 2015

maths
From the timing at 3:00, we see that the intervals are 15 seconds long. 12:00 is 12 strikes, but only 11 intervals.
December 20, 2015

math
Better check your math. The markup is not 36%, since the 10% discount also applies to part of the markup. Try some actual numbers.
December 20, 2015

math
If there is a markup of m, then we have (1+m) * .90 = 1.26 m = 0.4, or 40% Draw the chord, and a radius which bisects it, and the radii to the two ends. Then you will note that you have two 3-4-5 right triangles. So, the chord length is 6.
December 20, 2015

Maths
Assume the base is along the x axis. Assuming the vertex is between the ends of the base and has x-coordinate v, then if the two sides have equations y = mx+n and y = hx+k, then just integrate ∫[0,v]∫[0,mx+n] dy dx + ∫[v,a]∫[0,hx+k] dy dx If v is not ...
December 20, 2015

St. Vivekanand sr. sec. school,bikaner
assuming you mean i = √-1, then since i = 1 cis π/2, i^i = 1 cis (π/2 i) = cos(π/2 i) + i sin(π/2 i) = cosh(π/2) - sinh(π/2) = e^(-π/2)
December 20, 2015

calculus
clearly, we want f'(x) = 3ax^2 + 2bx + c to be zero at x= -5 and 4. So 3ax^2 + 2bx + c = k(x+5)(x-4) = kx^2+kx-20k so, c=-20k, 2b=k, 3a=k and f(x) = (k/3)x^3 + (k/2)x^2 - 20kx + d f(4) = 64k/3 + 8k - 80k + d = -152k/3 + d = -4 f(-5) = -125k/3 + 25k/2 + 100k + d = 425k/6 + ...
December 19, 2015

Math
y > 3x+10 y < 3/4 x - 1 So, graph the two lies. Shade the area above the first line, and below the 2nd line. Use dotted lines. (why) Does (8,10) fit both inequalities?
December 19, 2015

Trigonomentry plz help
taking reciprocals, we have cot^2A = 1/n^2 cot^2B csc^2A = 1/m^2 csc^2B m^2 csc^2A - n^2 cot^2A = csc^2B-cot^2B = 1 Now you should be able to get things down to cos^2A
December 19, 2015

Trigonometry- ??????
to explain, just evaluate: |a| = √200 |b| = √41 a+b = (14,15) |a+b| = √394 19.85 |a|+|b| = √200+√41 = 20.55 Seems clear to me. if a and b are two sides of a parallelogram, a+b is the diagonal. Clearly the indicated values cannot be equal unless a ...
December 18, 2015

Math
490 * 1.11^10
December 18, 2015

Tech
what do you mean by "the pitch"? An audio file contains many pitches. You want the whole file to be a single frequency at a constant volume?
December 18, 2015

Math
well, I'd guess that would be 1/2 of 2/3 So, what's 1/2 of 2? Take that many "thirds"
December 18, 2015

algebra
how about: what percent of 2 is 1? How did you get that? Do the same with 7 and 21.
December 18, 2015

algebra
Just read what it says, and write it down in symbols: If we start out with x = Rudolph's bells y = Dasher's z = Dancer's after step 1 we have x-y-z 2y 2z After step 2 we have 2(x-y-z) = 2x-2y-2z 2y-(x-y-z+2z) = 3y-x-z 4z After step 3 we have 4x-4y-4z 6y-2x-2z 4z-(...
December 18, 2015

Math
100,000,000*(1+.045)^2 I suggest you try investing $1000 first.
December 18, 2015

sri sri ravishankar
17 present means 21 absent. So, what fraction is that?
December 18, 2015

Pre Calc
You may find this easier if you let u = e^x. Then you have u^3-9u^2+20u = 0 u(u^2-9u+20) = 0 I think you can probably factor that. Of course, one solution is u=0, or e^x = 0 But that never happens, so you can throw it out.
December 18, 2015

Pre-calculus/ trig
a-b = -(b-a) so, they are vectors of the same magnitude, but in opposite directions. as you know, a+b is like the diagonal of a parallelogram with a and b as two sides. a-b is the other diagonal.
December 17, 2015

help
read the question. Read it again, carefully. Organize your thoughts. Write an introductory paragraph, present each of your discussion points, and summarize at the end. And google the topic. You will find as much detail as you can stand.
December 17, 2015

Trigonometry- Help!
the distance gone is √(200^2+300^2) = 100√13 = 360.55 That was done in 1 hour, so it's also the plane's speed, in mi/hr. Assuming it started at the airport...
December 17, 2015

Help!!
get off Jiskha and study the materials you've been given...
December 17, 2015

Math
could be either, depending on the rate. Increasing by 5 per day might be a lot worse than a 0.01% increase Or, a 2% increase might get a lot worse than 25 per day.
December 17, 2015

precalculus
the (x-2)^2 is always positive So, for -4 < x < -2, one of the other factors is positive and the other negative. watch out to exclude y=0 from your intervals.
December 17, 2015

Math
If y = f(g(x)) dy/dx = dy/df * df/dg * dg/dx = -csc^2(π/4 u)(π/4) * 6/2√x = -3πcsc^2(u)/4√x or, directly, y=(f◦g)(x) = cot(π/4 * 6√x) = cot(3π√x/2) y' = -3πcsc^2(3π√x/2) ---------------------- 4√x
December 17, 2015

Physics
weight is force = mg g = 9.8.
December 17, 2015

Math
bottom: 15*30=450 ft^2 sides: 2*15*5 + 2*30*5 = 450 ft^2 So, now you know the total area, and how much each can will cover...
December 17, 2015

@Go with MsSue
oops - Ms Sue did it right. I was calculating the cost per dozen, not each.
December 17, 2015

Math
well, 50¢/5 = 10¢ each. So, how much does a dozen cost at that rate?
December 17, 2015

Math Help ASAP PLZ!!!!!
no problema. Soon you'll be providing opaque and complicated answers for others! ͡° ͜ʖ ͡°
December 17, 2015

Math Help ASAP PLZ!!!!!
5 parts + 3 parts makes 8 parts in total So, divide 4 gallons into 8 parts, and each part is 1/2 gal. White gets 5 parts, blue gets 3. So, white = 5/2 or 2.5 gal.
December 17, 2015

Math
at t=pi/6, y=1/√3 and x=2/√3 So, now you have a point (2/√3,1/√3) and a slope (2), so the line is (using the point-slope form) y - 1/√3 = 2(x - 2/√3)
December 17, 2015

Algebra
hint: factors of 70 are 7 and 10
December 17, 2015

physics
depends on the friction between the surfaces. Among other things...
December 17, 2015

Physics
no idea. Is it in some position related to the springs?
December 17, 2015

PHYSICS
g = 9.81 weight = m*g on earth
December 17, 2015

Physics
what is the force acting downhill? F = ma
December 17, 2015

Science
but why is there such a difference? What does age have to do with the C14 reading? What does a reading of 76% mean? Rocks require a different measuring tool, but the method is basically the same; not sure they require any more effort.
December 17, 2015

eggs
maybe it was a stone sculpture of an egg. Or, maybe the egg had been soaked in vinegar, so it was all rubbery. Or, maybe it was a hard-boiled egg. Or, maybe there were feathers on the block. Or, maybe it was thrown on a small asteroid, so gravity was very weak. Questions like ...
December 17, 2015

math
The same variable on both sides? If not, just any linear equation with two variables will work, such as 2x+3 = y-7 You can pick any value for x (or y) and find a solution for the other variable.
December 17, 2015

math help plz?
Not at all. Which choice has a > sign? He wants to grow "more than" some amount. And come on, think- the kid is 61 inches tall now. He wants to be more than 70. So, what's the difference?
December 17, 2015

math help plz?
well, I only see one choice where the result is more than 70; all the rest are less.
December 17, 2015

Math GP
If I can inject a little sense into that, how about ar = a+2 a/(1-r) = 50 That has no real solution, but if you want a sum of -50, you can try a = -10 r = 4/5 -10, -8, -32/5, -128/25, ...
December 17, 2015

algebra 2
If you enter your polynomials at http://calc101.com/webMathematica/long-divide.jsp you can see all the details, with a little less noise.
December 17, 2015

International business
poorly punctuated and capitalized. Other than that, have you any ideas of your own to evaluate?
December 17, 2015

Math dumping
Also, homework dumps with no indication of any effort on your part tend to get scant attention...
December 17, 2015

science
well, since potential energy is mgh, and m and g do not change, I'd say the height is reduced by 40%, or 6m.
December 17, 2015

Science
recall Kepler's 3rd law: P^2/a^3 is constant Now we have to interpret your statement. As it is, it is rather ambiguous. Read it carefully. Assuming the most convenient meaning, I'll say that if we substitute 4a for a, we have to find P' such that P'^2/(4a)^3 = ...
December 17, 2015

maths
Figure how many days in that period. If using a 360-day year, then if there are k days, the interest is 850 * .05 * k/360
December 17, 2015

MATHMATHICS
They planned to build n+4 rooms, but built only n 1200/n = 1200/(n+4) + 10 Without even doing the math, recall that 1200 = 24*50 = 20*60
December 17, 2015

Math
if the length is x and the width and partitions is y, then 2x+4y = 80 x+2y = 40 xy = 192 So, which pairs factors of 192 add up as needed? 1 192 2 96 3 64 4 48 and so on. In the list you will find the pair(s) you need.
December 16, 2015

math
that would be 3/8 of the total, or (3/8)(32)(0.65)
December 16, 2015

business marh
well, just plug in 2 or 12 for n in 12000 (1+.03/2)^(2n) you can use google or wolframalpha to evaluate easily
December 16, 2015

Math
2(2-2x) = -3x distribute the 2: 4-4x = -3x now add 4x: 4 = x --------------------------------------- 3.75x+3.7 = 1.7+1.75x subtract 1.75x: 2x + 3.7 = 1.7 subtract 3.7: 2x = -2 divide by 2: x = -1
December 16, 2015

Math
correct
December 16, 2015

Math
#1 Nope. subtract 10, and you have x/4=4 #2 Nope. 4-4x = -3x #3 Nope. 2x = -2 Either you are trying to take shortcuts, or you really need to review how to collect terms and solve an equation.
December 16, 2015

Algebra
w(2w-4) = 96 now expand and solve the quadratic. Note that two factors of 96 are 8 and 12.
December 16, 2015

Marketing
well .60p = p-40
December 16, 2015

math
well, 3x+2 + 5x+8 = 90 8x = 80 ...
December 16, 2015

Grammar
13 is a noun, used as an adjective, as often happens in English. 14 is a noun Looks good otherwise.
December 16, 2015

Not surprising
since no question was posed, just a murky and cryptic expression. Next time, SHAELYNNN, try to be it clear just what it is you need help with. We tend to ignore postings where we have to figure out the question as well as the answer!
December 16, 2015

ALGEBRa 2
f(x) = 2x^3 - 4x^2 + 8x - 3 so, if x = -2, just replace all the x's with (-2)'s: f(-2) = 2(-2)^3 - 4(-2)^2 + 8(-2) - 3 = 2(-8) - 4(4) + 8(-2) - 3 = -16 - 16 - 16 - 3 = -51 Note how much clearer using ^ for powers is than all that wordy mumbo-jumbo.
December 16, 2015

MATH
no idea how that would help find the experimental probability. That is determined by performing the experiment some large number of times. Now, if you expect a probability of 75%, then your spinner should have 3/4 of its area labeled success, and 1/4 failure. Then spinning the...
December 16, 2015

physics
assuming an exponential function with initial value f(t) = a, a*e^-kt, we have a*e^-7k = 518 a*e^-17k = 156 so, dividing, e^10k = 156/518 k = -0.12 f(t) = ae^-.12t a*e^-.84 = 518 a = 1200 f(t) = 1200 e^-0.12t
December 16, 2015

physics
well, under acceleration, the height h is h(t) = (1/2)90.3 t^2 At t = 1.75, the height is 138.27 m Since v = at, at t=1.75, the upward velocity is 158.03 m/s Now it goes ballistic (really!) and the height is given by h(t) = 138.27 + 158.03t - 4.9t^2 That's just a parabola...
December 16, 2015

physics
figure the angle θ between the lines AB and BC. Then use the law of cosines to get AC. AC^2 = 61^2 + 98.1^2 - 2(61)(98.1)cosθ Or, you can use the law of sines twice to find angle C and then AC.
December 16, 2015

Math 6/7
Also, if the fraction has a denominator that has any prime factors other than 2 and 5, it cannot be expressed exactly as a decimal.
December 16, 2015

math please help i'm new
recall the Pythagorean Theorem. d^2 = 9^2 + 12^2 = 81+144 = 225 do, d=15 Also, it helps to recall a few simple and commonly used right triangles. The most basic is 3-4-5 Your 9-12-15 triangle is just a 3-4-5 scaled up by a factor of 3.
December 16, 2015

Algebra
I/R = k, which is constant, so you want I such that I/20 = 21/5
December 16, 2015

ggs
First, fix what's missing at C-+A And it looks like a lot of garbage, since A+A+A = A and so on
December 16, 2015

math + ms. sue please
you are correct. DE/40 = 3/15
December 16, 2015

Algebra
depends on the total amount invested. Could be anywhere from $13333 at 9% and $0 at 11% to $0 at 9% and $10909 at 11%
December 16, 2015

Algebra
No inequalities here. a = o-1 p = 2a a+o+p = 17 Let's find out how many oranges: (o-1) + o + 2(o-1)) = 17 4o-3 = 17 4o = 20 o = 5 So, there are 4 apples 5 oranges 8 pears
December 16, 2015

Algebra
go to http://www.wolframalpha.com/input/?i=-2%2F3x%3C8 and scroll down a bit
December 16, 2015

Trigonometry
Draw a diagram. Use the law of cosines, since you have two sides and the angle between them, and want to find the 3rd side. To get you started, the angle between the two sides is 33.25+13.25=47.5° actually, that's (270-236.25)+(103.25-90). To get the side lengths, ...
December 16, 2015

math
Didn't you just say that Tom can do it in 3 days? Since each of them can do the job in 3 days or less, how can it possibly take them 15 days to do it together? Something is seriously bogus here.
December 16, 2015

Pre-calculus: Logarithms
not true. the quotient of logs is like a change of base ln56/ln7 = log756 In this case, it's easy to find out whether it's true or not: ln56 = 4.025 ln7 = 1.946 ln8 = 2.079 4.025/1.946 = 2.068 ≠ 2.079 ln56 - ln7 = ln(56/7) = ln8
December 16, 2015

ebusakami girls
doesn't matter in this case. One mole of CaCl2 or CaCO3 contains exactly 1 mole of Ca++ ions.
December 16, 2015

Mathematics
Factor is a verb. Or, you can say factorize (no doubt, factorise in Britain), but never factorice. 16(a-2b)^2 - (a+b)^2 is the difference of two squares, so its factors are (4(a-2b)+(a+b))(4(a-2b)-(a+b)) = (4a-8b+a+b)(4a-8b-a-b) = (5a-7b)(3a-9b) = 3(5a-7b)(a-3b)
December 16, 2015

Algebra
add up the values: 5n + 25(26-n) = 410
December 16, 2015

Algebra
#1 ok #2 missing a y value #3 ok #4 C .984 is very close to 1, which is an exact match.
December 16, 2015

Algebra
#1 C did you actually check the differences? #2 D (3-8)/(2-(-6)) = -5/8 #3 D better review that topic #4 B same advice #5 C same advice #6 C they are the same equation Next time you want a check on your work, it would be better to show what you did.
December 16, 2015

Math
Is that 1/2 outside also an exponent? If so, (2^-5 * 2^-6)^(1/2) (2^-11)^(1/2) 2^(-11/2) recall that x^m * x^n is the same as xxxxx(m times)*xxxx(n times) = xxxx(m+n) times = x^(m+n) (x^m)^n = x^m * x^m ... (n times) = x^(m+m+m...n times) = x^(m*n)
December 15, 2015

math
well, without knowing the prices, it's hard to say. However, your net pay per hour is 15(1-.0765-.12-.08) = $10.8525
December 15, 2015

Pythagorean Theorem
hint: 36=12*3 and 48=12*4 I'm sure you know that a 3-4-5 triangle is a right triangle.
December 15, 2015

math
I think you will have better luck working with the digits. Let the number have the digits xy So, its value is 10x+y. Now we have 10x+y = 8(x+y) 10x+y-45 = 10y+x Now you can easily discover that the number is 72
December 15, 2015

Maths
review your basic trig functions. You will see that the height h can be found using h/51 = tan 64°
December 15, 2015

Maths
you want an angle of x, where tan(x) = 2/1 The rest just use the Pythagorean Theorem.
December 15, 2015

Algebra
just use the facts given: 8d+12g = 120 5d+4g = 61 Now just solve the system.
December 15, 2015

Theory of interest
Ω
December 15, 2015

math
No idea. All I have is a point and a line. A and B could be anywhere on the line.
December 15, 2015

Geometry
you have, since the angles sum to 180, 5x+10+3x+18+2x+32=180 10x+60=180 10x=120 x=12 Now you can find out the angles, and classify the triangle.
December 15, 2015

Math
divide all lengths by 20 and use in instead of ft divide all areas by 20^2, and use in^2 instead of ft^2. The base is square. Any sections parallel to the base will naturally also be square.
December 15, 2015

algebra (check answers)
#1 ok #2 Nope. Try (a) since you have to subtract 1/8 from both sides. #3 d (-6)(-15) = +90 3(c) is exactly what they did wrong. You want to correct the mistake, not repeat it.
December 15, 2015

Geometry
must be, since LM ⊥ LN
December 15, 2015

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