Thursday
August 25, 2016

Posts by steve

Total # Posts: 42,758

Java programming
I'm sure you can do the I/O. The calculation is v = Math.PI * r*r * h a = 2*Math.PI * r * (r+h) or, for r-squared, there's always Math.pow(r,2)
August 13, 2016

Maths
(1) 16(1 - 1/2^10)/(1 - 1/2) (2) 1/9 (3^8 - 1)/(3-1) see how these match up with your general formula.
August 13, 2016

math
6250(1 + r/4)^2 = 6760
August 13, 2016

physics
Since 100°C = 60°M, the C degrees are 3/5 as big as the M degrees. so, C = 3/5 (M-20) + 0
August 13, 2016

science
it is where all motion stops. It can never be achieved, due to the Heisenberg Uncertainty Principle. But, we've gotten mighty close: 0.0025°K 0°K = -273.15°C 0°R = -459.67°F
August 13, 2016

Math
just solve for t in -16t^2+86t+212 = 320
August 13, 2016

Math
7x + x^2 = -12
August 13, 2016

math
3x-6 = 66
August 13, 2016

geometry
(11+2w)(6+2w) - 11*6 = 28 now just solve for w
August 13, 2016

math
since primes must end in 1,3,7,9 there are only a few decades to check.
August 13, 2016

math
If the mug holds x ml, then x/2 + 25 = 3x/5 Now just solve for x
August 13, 2016

Pre-Calculus
since sec^2Θ = 1+tan^2Θ yes, up to the sign. secΘ might be plus or minus for a given value of tanΘ.
August 12, 2016

Algebra
h(x) = 2x^2-7x the average rate of change is just the slope of the line from (1,h(1)) to (5,h(5)). That is, (h(5)-h(1))/(5-1)
August 12, 2016

Maths
multiply top and bottom by 1+sin+cos For ease of reading, I'll just use s and c for sinx and cosx (1+s+c)/(1+s-c) * (1+s+c)/(1+s+c) = (1+s+c)^2 / ((1+s)^2 - c^2) = (1+s^2+c^2+2s+2c+2sc) / (1+2s+s^2-c^2) = (2+2s+2c+2sc)/(1+2s+s^2-1+s^2) = (2+2s+2c+2sc)/(2s+2s^2) = ((1+c)(1+...
August 12, 2016

Math
well, |-8| = +8 so, what do you think?
August 12, 2016

Algebra
your copy/paste is running into some font problems. My browser does not properly display ¨C or ¡Ù I'm guessing they are - and ≠ If I'm right, then The opposite of -4 is 4 (though "opposite" is a rather vague mathematical term) The ...
August 12, 2016

math
perimeter can be irrational and area rational, since the nonzero sum of two irrationals is irrational the product of two irrationals may be rational √5 * √5 = 5
August 12, 2016

Stats
since the draws are independent, just multiply their probabilities: 3/9 * 2/8
August 12, 2016

math My Bad^2
Sorry, Bosnian. Blew that, too.
August 12, 2016

math - MyBad
Damon has it right What was I thinking???
August 12, 2016

math
Look at the table. x changes by +2 y changes by -1 The slope is the ratio of changes, y-change / x-change = -1/2 So, the answer is g if there is a typo and it reads -1/2
August 12, 2016

algebra 2
trick answer! Nice one.
August 12, 2016

math
90/(7+8) = 90/15
August 12, 2016

math
after 28, there were 14 below 3 and 14 above 2. So, what do you think? Check the last two throws. 30*3 = 90 The sum of 28 throws was 78, so the last two had to add up to 12.
August 12, 2016

precal
moving right along, you know that the parabola x^2 = 4py has focus at (0,p). You have (x-3)^2 = -5(y+5) So, 4p = -5 and the focus is at (0,-5/4) but shifted by (3,-5) to (3,-25/4) as Reiny's graph shows.
August 11, 2016

Geometry
much better.
August 11, 2016

Geometry
I like C more. When the final arrives, he'll do better if he has reviewed and learned his previous material. D is just wishful thinking.
August 11, 2016

Math
4000(1 + .048/12)^(12*9) I'm sure your book has the formula A(1+r)^t you have to adjust it if the rate is compounded more than once per year. If monthly, then n=12 times per year. Thus, the monthly interest is 1/12 the annual rate, and there are 12 times as many ...
August 11, 2016

Calculus
see the related questions below. Solutions are provided, just using different values. If you get stuck, come on back with what you have so far. Try this one: http://www.jiskha.com/display.cgi?id=1226871282
August 11, 2016

Math
to get the graph, just graph them... To find where the graphs intersect, solve algebraically y^2-2x+2=0 and x-y-5=0 x=y+5, so y^2-2(y+5)+2 = 0 y^2-2y-8 = 0 (y-4)(y+2) = 0 Now you know y, so you can get the corresponding x values. 2x^2+3y^2=21 3x^2-4y^2=23 8x^2+12y^2 = 84 9x^2-...
August 11, 2016

Algebra simplifying fractions
5y(2y-1) / 5y = ?
August 11, 2016

Algebra
(m^2+mn)/(m^2-mn) = m(m+n) / m(m-n) = (m+n)/(m-n)
August 11, 2016

math
x + 2/3 x = 180
August 11, 2016

Vector , physics
by symmetry, it is clear that AB+AF = k1*AO AC+AE = k2*AO AD = 2AO Now you should be able to show that k1+k2 = 4
August 11, 2016

jangid
without going through all the algebra, recall that 120 = 5! = 1*2*3*4*5 That help?
August 11, 2016

Math
geez, 11 minutes? impatient much?
August 11, 2016

Math
If there are n cards, then n is a multiple of 2. so, you want an even number which is 3a+2 or 5b+1 a must be even and b must be odd. 26 = 3*8+2 = 5*5+1 = 2*13
August 11, 2016

Calculus
yes, those are the two values in the interval [0,2pi)
August 11, 2016

Algebra
3x5+4-2x2+6-4=15 since the only two odd numbers are the 3x5, and only the product of two odds or the sum of an even and an odd is odd, we must have either 3x(5...) or (3x5)+... see what you can do with that
August 11, 2016

Probability
well, 19 of the 20 stamps have some blue or red, right?
August 11, 2016

math
The 1st number is larger than the 2nd: a/b = (5/6):(2/3) = 5/4 So, a = 5/4 b = b * 1.25 so, a is 25% larger than b
August 10, 2016

Sum of geometric sequences
a=5 r=3 S10 = a(r^10-1)/(r-1) plug and chug
August 10, 2016

Calculus
better use implicit differentiation: e^(xy) = sinx e^(xy)(y + xy') = cosx x e^(xy) y' = cosx - y e^(xy) y' = (cosx - y e^(xy))/(x e^(xy)) but e^(xy) = sinx, so y' = (cosx - y*sinx)/(x*sinx) y' = (cotx - y)/x or, using logs, e^(xy) = sinx xy = ln(sinx) y + ...
August 10, 2016

Calculus 1
try using the binomial expansion. You will see that the expression is e^(6/x)^(x/2) + (x/2)e^(6/x)^(x/2-1)(8x) + ... = e^3 + 4x^2*e^3/e^(6/x) + ... where all the rest of the terms ->0 so, the limit is e^3
August 10, 2016

Calculus
surely you can find the derivative of both top and bottom, no?
August 10, 2016

science
clearly, that would be 400N/cm^2
August 10, 2016

MATH
what sentence? All I see is an expression.
August 10, 2016

Geometry
15 seconds * 5rpm = 5/4 rev So, after 15 seconds, it has rotated 1 1/4 times. I am also having trouble getting the given matrix. How does it rotate? What is the axis of rotation?
August 10, 2016

Chemistry
since 1mL = 1 cm^3, 16.3 cm^3 * 10.5g/cm^3 = 16.3*10.5 g
August 10, 2016

Chemistry
use the density of Al to find the volume occupied by 54g g ÷ gm/cm^3 = cm^3
August 10, 2016

Pre-Calc
There are no intervals involved. since sin(π/4) = 1/√2 the principal value of arcsin, Sin^-1(1/√2) = π/4 But, since there are many other angles, sin^-1(1/√2) = π/4 or 3π/4 and since the period of sin(x) is 2π, sin^-1(1/√2) = &#...
August 10, 2016

Math
If you mean scale factor, then you multiply whatever dimensions you have by the scale factor.
August 10, 2016

algebra
12/2 (2a+11d) = 168 a+6d = 7 Now just solve for a and d.
August 10, 2016

Math
try 500x > 5280 or, x > 5280/500
August 10, 2016

math
minor sector: a = 1/2 r^2 θ = 1/2 * 25 * π/3 = 25/6 π no idea where A and B are, but angles do not have areas. minor segment: 1/2 r^2 (θ-sinθ) = 1/2 * 25 (π/3 - √3/2) arc length = rθ = 5 * π/3 = 5/3 π I see you found the area ...
August 10, 2016

Maths
in English, there are no ands in writing large numbers. So, four hundred one thousand eight hundred nine = 401,809
August 10, 2016

History
thank you
August 10, 2016

History
Many changes occurred to the a freedman's life during reconstruction. Which of the following freedoms did these individuals gain? 1- right to legalize a marriage and raise a family 2- freedom to choose where to live 3- freedom to establish churches and community centers 4...
August 10, 2016

Math
compare the unit prices: $5.99/2L = $2.995/L and $2.95/.75L = ? $/L
August 10, 2016

math
100-(80+85-73) = 8
August 10, 2016

probability statistics
For A and B, just divide the number of your color by the total. For example, P(blue) = 7/20 D is a trick question.
August 10, 2016

algebra
ok - what is the cost? did you use an editor?
August 10, 2016

algebra - typo
what does ^0.3x mean? should there be an x^2 in there somewhere? or just .03x ?
August 10, 2016

math
Efa started out right, but then lost track of the math. 100% is 10 times 10% So, the full tank is 10 times 30L = 300L
August 10, 2016

physics
PV=k so, P*8 = 48*15
August 10, 2016

Math
7 days @ 6 per day is 42 eggs for the week. So, add up the rest and see how many were needed to get to 42.
August 10, 2016

chemistry
well, you can start off with 2NH3 = N2 + 3H2 now start by changing moles
August 10, 2016

Discrete Mathematics and its Application
By "truth" do you mean a truth table? If so, just list the 8 rows and the 8 values of the functions, and it is easy to show which are equivalent.
August 9, 2016

Math
In terms of cm, 57m 50cm = 5750cm 22m = 2200cm The greatest common factor can be found using 5750 = 2 * 5^3 * 23 2200 = 2^3 * 5^2 * 11 So, the GCF is 2*5^2 = 50 Using 50cm stones, the courtyard is 115x44 = 5060 stones
August 9, 2016

math
huh? None of the above. The total marks for the 10 students is 10*8 = 80 I suspect you have left out something, like the size of the group.
August 9, 2016

Reposting question- Pre-calc
Excuse me?? Can you not just plug in the x-value? y = 5cot(-2x) so, at x = π/6, y = 5cot(-2 * π/6) = 5cot(-π/3) = -5cot(π/3) = -5/√3
August 9, 2016

Maths
See the related questions below. A good one is http://www.jiskha.com/display.cgi?id=1353315962 not quite yours, but very close.
August 9, 2016

Mathematics
In English, I think this reads A parking lot has a capacity of 75 cars. If 3/5 of it is full at one time, how many more cars can be parked? Well, 3/5 of 75 is 45, so what do you think?
August 9, 2016

Maths
google cylinder inscribed in cone and you will find may expositions of a cylinder inscribed in a cone of base radius R and height h. The only twist to your problem is that you have h and α instead of h and R. If you draw a side view, it its clear that R/h = tan α Now...
August 9, 2016

Math
e^(.09t) = 2 now solve for t years
August 9, 2016

Math
5 * 12.3 = 61.5 That is the total of the 5 numbers with that average. So, the missing number is 61.5 minus the sum of the first 4 numbers.
August 9, 2016

math
497
August 9, 2016

math
One thousand people stood in a very large circle. Each starting with the Jennifer Lopez look alike, wore a sign on his or her back with a numeral from 1 to 1000 in a clockwise sequence. They began counting off. The Jennifer Lopez look alike said one in and remained in the ...
August 9, 2016

math
42
August 9, 2016

ap chemistry
(3 mole N)/(1 mole Al(NO3)3) * (.75 mole Al(NO3)3)/L * 0.40L = (0.9 mole N)
August 9, 2016

Science
(3x)^2 + (5x)^2 - 2(3x)(5x)cos120° = 28 9x^2 + 25x^2 +15x^2 = 28^2 x = 4 So, the two forces are 12 and 20 check: <12,0> + <10,10√3> = <22,10√3> magnitude is 28
August 9, 2016

Mathematics
If you mean (1+ax)/(1-ax) = p/q q(1+ax) = p(1-ax) q + aqx = p - apx aqx+apx = p-q x(ap+aq) = p-q x = (p-q) / a(p+q)
August 9, 2016

science
think of a weight w on a horizontal plane (θ=0). All of the force is downward. That means that perpendicular is w*cosθ parallel is w*sinθ As the board is tilted, less and less is perpendicular, and more and more is parallel
August 9, 2016

Statistic
the possibilities are, of course, 0R 6W 1R 5W 2R 4W So, can you determine how many ways for each of those setups?
August 8, 2016

Calc - help needed
You did not read the domain carefully, nor did your points meet the requirements. All of your points are in QII and QIV, where tan(x) = -1/√3 The domain is [-3π/2,2π], and all of your points must lie in QI or QIII, where tan(x) > 0 That would mean that the x...
August 8, 2016

Algebra Quadratic Functions
as usual, the vertex is at s = -b/2a = 3/2 y(3/2) = 25/4 so far, so good. So, when does it hit the ground? When y=0, naturally. So, -s^2+3s+4 = 0 (s+1)(4-s) = 0 so, it hits the ground after 4 seconds.
August 8, 2016

statistics
Just as the median is the middle point in the range, the 1st quartile is the middle point in the lower half. Your data set is so small that it's hard to divide equally. But, the url below discusses it in some detail. https://en.wikipedia.org/wiki/Quartile
August 8, 2016

math quadratic functions
If x is one side, let y be the other. Then 4x+4y = 40 x+y = 10 y = 10-x The total area is thus a = x^2+y^2 = x^2 + (10-x)^2 = 2x^2-20x+100 a has a minimum at x = 20/4 = 5 As expected, minimum area occurs when the two squares are in fact equal.
August 8, 2016

Algebra Quadratic EFuncyoon
the maximum area is at the vertex of the parabola. That is always at the axis of symmetry, x = -b/2a In this case, that is at x = 100/4 = 25 2*25^2 - 100*25 = -1250 ??? Your function cannot be correct, since it is a parabola opening upward, and thus has no maximum. The ...
August 8, 2016

Math
6n+7p = 2170 If he had x cents left, then 7n+7p = 2170+x+30 6n+8p = 2170+x-50 x = 180 n = 210 p = 130 So, a notebook costs $2.10
August 8, 2016

Calculas
well, the slope is 3/4 so plug that into the other forms. y = 3/4 x + ? y-k = 3/4 (x-h)
August 8, 2016

Math
28-6n+7(5n-2)-2n 28-6n+35n-14-2n ...
August 8, 2016

Math
no, -130-48 = -178 if you think the other way around, the depth started at 130 and then was reduced by 48 as the penguin rose 130-48 = 82 or, as feet from the surface, -130+48 = -82 Get out your number line, and remember that negative means go left, and positive means go right...
August 8, 2016

Math
-130 + 48 = ?
August 8, 2016

How's that again?
you want to reword that so it makes sense?
August 8, 2016

Math
Nope. It's 8^-3, or 1/8^3 B
August 8, 2016

Maths B
.75m/s * 60s = 45m Draw a diagram. It will show that y cot 30° - y cot 50° = 45
August 8, 2016

Mathematics
7(x+4) - 2/3 (x-6) < 2(x-3(x + 5)) 7x+28 - 2/3 x + 4 < 2x - 6x - 30 19/3 x + 32 < -4x - 30 31/3 x < -62 x < -6
August 8, 2016

precal
I assume you mean 2sin2x - 2cosx = 0 4sinx cosx - 2cosx = 0 2cosx(2sinx-1) = 0 so, cosx = 0 or sinx = 1/2 so, there will be four solutions in [0,2π)
August 8, 2016

Physics - eh?
how can you have a depth of 10 meters per second ???
August 8, 2016

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