Sunday
August 30, 2015

Posts by steve


Total # Posts: 33,138

Physics
first, dodos do not fly. second, dodos are extinct. However, since time=distance/speed, if the bird flies back x km, then (4.9+x)/24.8 = (4.9-x)/6.2 x = 2.94 So, the bird flew 7.84 km
August 20, 2015

Math - eh?
you want to try that again in English?
August 19, 2015

Math
32% = 0.32 "of" means multiply: half of 6 is 1/2 * 6 = 3 So, you want 0.32 * 250
August 19, 2015

Math
3 of the fruits are not apple or peach. So, p=3/12
August 19, 2015

Calculus
while x < 2, -2 < 0, so, |x-2| = -(x-2) So, you have the limit of (3x(-(x-2)))/(x-2) = -3x You can cancel the x-2 since x is not actually 2. The limit is thus -6 The limit from the right, of course would be +6 See the graph at http://www.wolframalpha.com/input/?i=%283x+|...
August 19, 2015

Solid Mensuration
I suspect it will be 4x8, but let's see what the calculations show. If triangle ABC has vertices at (0,0),(16,0) and (h,8) then the sloping sides are lines with the equations y = 8/h x y = 8(x-16)/(h-16) Now, suppose the inscribed rectangle has height k. The the line y=k ...
August 19, 2015

Trig
2sinθ+1 = 0 2sinθ = -1 sinθ = -1/2 sin π/6 = 1/2, so using that as a reference angle in QIII and QIV, we get the solutions π + π/6 and 2π - π/6
August 19, 2015

Geometry
well, UV bisects STU, so 1/4 x + 8 = x+2 6 = 3/4 x x = 8 Now you know x, so you can figure STV=VTU, and STU = STV+VTU I get 20 How did you get 25?
August 19, 2015

Math
I think you mean (8 * 2^10)^2 * 3^7 (2^13)^2 * 3^7 2^26 * 3^7 67108864 * 2187 146767085568 Clearly I have misinterpreted your unusual syntax.
August 19, 2015

Math
36*10/24 = 15
August 19, 2015

Math
5n+10(8-n) = 65 -5n = -15 n = 3 she spent 3 nickels and 5 dimes. So, starting with N nickels and D dimes, 5N+10(20-N) = 140 -5N = -60 N=12 So, she is left with 9 nickels.
August 19, 2015

Geometry
since R is the midpoint of ST, SR is 1/2 ST, so 2(3x+3) = 30 3x+3 = 15 3x = 12 x = 4 not sure what you mean by x being 9 to equal 15
August 19, 2015

Calculus 1
the roots indicate that f(x) = a(x+1)(x)(x-2) Since f(1) = a(2)(1)(-1) = -2a = 8, a = -4
August 19, 2015

algebra
Or, using y(x) = -9/2 x + 3, y(-2) = 9+3 = 12 You want y(-2) = 5, so you have to subtract 7 from the given value, leaving you with y = -9/2 x - 4
August 19, 2015

ethics
google turns up http://www.studydroid.com/printerFriendlyViewPack.php?packId=373583 It would have worked for you, too.
August 19, 2015

algebra
type in your expression at wolframalpha.com It will show the graph. Play around there a while.
August 19, 2015

Math-unit rate
(1 1/2 mi)/(3/5 hr) = (3/2 mi)/(3/5 hr) = 5/2 mi/hr or, 2 1/2 mi/hr if you like mixed numbers
August 19, 2015

algebra
It always helps if you show your work. If it is wrong we can spot the error. Assuming the usual sloppiness with parentheses, I will assume you meant (44/9)x - 7/4 + (12/7)x + 1 = (44/9 - 12/7)x - 7/4 + 1 = (200/63)x - 3/4 I might have thought you were using x for ...
August 19, 2015

algebra
y = mx+b where m is the slope b is the intercept just plug in your values.
August 19, 2015

pre algebra
-|-16| = -16 since |-16| = 16
August 19, 2015

MATH
12/60 = 0.2
August 19, 2015

algebra
y=0 is the same as y = 0x+0 so, its slope is zero. 9x+2y = -8 is the same as 2y = -9x - 8 y = -9/2 x - 4 so its slope is -9/2 Try the others. Rearrange stuff to get y all alone on the left side, as I did above.
August 19, 2015

algebar
two lines are perpendicular if their slopes are negative reciprocals. That is, their product is -1. y = -x-3 has slope -1. So, its reciprocal has slope -1/-1 = 1
August 19, 2015

math
wow - at least you used "whom" correctly. If you are trying to find roots of cubics, you must have already studied quadratics and factoring, maybe even synthetic division. Can you find the roots of quadratics? Like x^2-x-2 = 0 If not, you can forget 3rd-degree ...
August 19, 2015

Math
eschewing all the words, we have 8^2 + 9(12/3 * 2) - 7 64 + 9(4*2) - 7 64 + 9*8 - 7 64 + 72 - 7 129 Now, since you were unclear about just what was being divided, you might have meant 8^2 + 9(12/(3*2)) - 7 64 + 9(12/6) - 7 64 + 9(2) - 7 64 + 18 - 7 75 Parentheses are your ...
August 19, 2015

Math
so, the ratio is 7:26
August 19, 2015

Math
well, how many total cubes are there? How many red?
August 19, 2015

math
there are only 2 numbers larger than 6, so p = 2/8
August 19, 2015

math
It's not at all obvious that you tried. I did the first one for you. Take a look at that one, and use the same method for the others. The chances are good that there will be at least one root that is easy to find. At least show what ideas you tried, which failed.
August 19, 2015

math
cubics are tough. Look for low-hanging fruit. Clearly there are no positive roots, since all the coefficients are positive. f(-1) = -1+6-12+8 = 1 f(-2) = -8+24-24+8 = 0 So, x^3+6x^2+12x+8 = (x+2)(x^2+4x+4) Now it's easy
August 19, 2015

Algebra II
looks good to me
August 19, 2015

Math
the ratio of height/shadow is the same for both objects. So, 51/48 = h/16
August 19, 2015

Math
the two angles must add to 180 degrees. So, to get <2, subtract <1 from 180 Complementary angles add to 90, so the complement of 2 is 90 - <2 Or to do it all in one step, if the measure of <1 is x, then the complement of <2 is 90-(180-x) = x-90
August 19, 2015

math
you have a problem with actual math symbols? 3/5 = 27/45 7/9 = 35/45 so, which do you think took less time?
August 19, 2015

math, science, everything else for 10th grader
secx = 17/8, so cosx = 8/17 sinx = 15/17 tanx = 15/8 Now just plug in your values: (3-4sin^2x)/(4cos^2x-3) = (3-4(15/17)^2)/(4(8/17)^2-3) = 33/611 (3-tan^2x)/(1-3tan^2x) = (3-(15/8)^2)/(1-3(15/8)^2) = 33/611
August 19, 2015

Math
Looking good. Nice work.
August 19, 2015

Geometry
the diameter is the distance between the two points: √((5-2)^2+(5-1)^2 = 5 Now it's a cinch, right?
August 19, 2015

Algebra
yes. commutative property of multiplication There is also a commutative property of addition, which could be written as (2 + p)(r + 9) = (p + 2)(9 + r)
August 19, 2015

Algebra II
transitive relates 3 values: a=b and b=c ==> a=c Clearly this is just a case of substituting z for y, since y=z.
August 19, 2015

maths
since r is constant, (1-t)/(2-5t) = (t+1)/(1-t) Solve that for t, and you will find that matching sequences are, with r=2 and r=1/3, 1/3, 2/3, 4/3, ... 9/2, 3/2, 1/2, ...
August 19, 2015

physics
Vy = 300-9.8t Vx = 519.6 So, at t=2, Vy = 280.4 Vx = 519.6 |v| = √(280.4^2+519.6^2) = 590.4 θ = arctan(280.4/519.6) = 28.4°
August 19, 2015

Physics
1.07 E = <1.07,0> .533 S = <0,-0.533> 4.62 @ W50.1°N = <-2.963,3.644> add them all up and you have a final displacement of <-1.893,3.111> = 3.642 @ N31.3°W now you can figure the velocity
August 19, 2015

Math
you are correct.
August 19, 2015

Math
well, 1364 = 14*93 + 62 17765 = 27*646 + 323
August 19, 2015

math
y = 3(x-2)^2+3 y' = 6(x-2) y" = 6 critical point is at x=2 minimum because y" > 0 there. http://www.wolframalpha.com/input/?i=3%28x-2%29^2%2B3 But then, you knew all that from Algebra I, right? Vertex of a parabola and all that.
August 19, 2015

math
the domain of rational functions is all reals except where the denominator is zero. x^2+8x+15 = (x+3)(x+5) So, I guess you can work it from there, right?
August 19, 2015

math
If you mean 10sin((x/4)-4π)-5 then that is 10sin((x-16π)/4)-5 period = 2π/(1/4) = 8π shift = 16π
August 19, 2015

Algebra
both right. good work. Of course, your nearest calculator could have confirmed your results...
August 19, 2015

Algebra
10(q-3) + 25q = 1300
August 18, 2015

Diff Calculus
When the water is y meters deep, the surface has a length of 5y and a width of 5. So, its volume is v(y) = 25/2 y^2 dv/dt = 25y dy/dt Now plug in y=1 and dv/dt=0.1 to find dy/dt
August 18, 2015

Math algebr
Looks like A to me.
August 18, 2015

Math dimensional anaylsis
9yd/3hr * 3ft/yd * 1hr/60min = 27/180 = 3/20 ft/min
August 18, 2015

algebra
just replace any x with -1, then simplify: 3(-1)^2-7 3*1-7 6-7 -1 you are correct
August 18, 2015

Calculus
you can always check your answers at wolframalpha.com As you can see, you're way off. If h = 3e^u where u is a function of x, then h' = 3e^u du/dx = 3e^(sin(x+2)) * cos(x+2) http://www.wolframalpha.com/input/?i=derivative+3e^%28sin%28x%2B2%29%29
August 18, 2015

Math
clearly the lines intersect where 1/4 x = -1/4 x 1/2 x = 0 x = 0 so, y=0 Looks like B to me. You can easily check to see that none of the other points lies on either line.
August 18, 2015

Math (Probability)
there are 3 numbers less than 4. So, 3/x = 1/10 ...
August 18, 2015

physics
well, the momentum has changed from 1500*40 to 1500*50 How hard is that?
August 18, 2015

Slope
recall the sloe-intercept form of a line: y = mx+b where m is the slope. slope is defined as the change in y, divided by the change in x. Since y=6x+3, y changes by 6 whenever x changes by 1. For, consider y(x) = 6x+3 y(x+1) = 6(x+1)+3 = 6x+9 x has changed by 1, and y has ...
August 18, 2015

Algebra
if you add the two equations, the x's cancel out, and you have 6y = -12 y = -2 so, x=2. The book answer is wrong. (6,-6) fits the 2nd equation, but not the 1st. If the 1st equation were -4x-2y = -12 then (6,-6) would be correct. So, it appears that the problem has a typo.
August 18, 2015

math sqrt root
x√2x + 2√2x^3 + 2x^2/√2x = x√2x + 2x√2x + x√2x = 4x√2x 2√(2x^3) = √((2x)(x^2)) = 2x√(2x) (2x^2)/√(2x) = = x√(2x)√(2x)/√(2x) = x√2x √(2/3) = √2/√3 = √2/√3...
August 18, 2015

Math (Calculus)
since 3 radians is in QII, sin is positive, and cos is negative. 3 is almost pi: 171.9 degrees
August 18, 2015

Algebra
vertical asymptote is ok horizontal asymptote is at y=1/3 (x^2+2)/(3x^2-5) = (1 + 2/x^2) / (3 - 5/x^2) as x gets huge, the fractions vanish, and we are left with 1/3 When the degree of top and bottom are the same, then the limit is the ratio of the coefficients of the highest ...
August 18, 2015

math
y = ax+bx^2 2a+4b = 14 5a+25b = 65 y = 3x+2x^2 take it.
August 18, 2015

Lyncheez Bee (math)
If the digits are xyz, then x+y+z=9 2y=x+z 2x=z The number is thus 234
August 18, 2015

maths
n=2k+1, so clearly n must be odd. Now, it is also 5k+4, so k must be odd since otherwise 5k is even, and so is n. Any odd multiple of 5 ends in 5, so n must end in 9.
August 18, 2015

maths
2400 is a multiple of 3, so y5 must be a multiple of 3. Can you think of any 2-digit multiples of 3 ending in 5?
August 18, 2015

Algebra
I can see the (a^3)^(1/4) in the denominator, but there's no way to get 648 in the top from what you have written.
August 18, 2015

maths
Do you mean a 4-digit number 91z5? The digits of any multiple of 9 add up to a multiple of 9. So, 9+1+z+5 = 15+z So, z=3 to make the sum 18. 9135 = 9*1015
August 18, 2015

maths
1.94 x 10^2 Not sure just what you're looking for.
August 18, 2015

pre-cal
Remember the law of sines? a/sinA = b/sinB 24/sin42° = b/sin87° Now you can find b with no trouble.
August 18, 2015

maths
Doing my best to parse the wordy and ambiguous notation, I get ((4/3)√3 - 2√2+3)/(3√3 + 2√2) No, that is too weird. How about 4/(3√3-2√2) + 3/(3√3+2√2) Now we can make a common denominator of (3√3-2√2)(3√3+2&#...
August 18, 2015

Math
If x gallons were poured, then (35+x)/(4.5+x) = 7/2 x = 7.7 Now it's easy peasy.
August 18, 2015

algebra
r^3 = 3/192 = 1/64 r = 1/4 So, use that to find x and y Or, you can say (x/192)^2 = 3/x x=48 y/48 = 3/y y=12
August 18, 2015

Math
rev/hr = rev/min * 60min/hr L/rev = L/hr * hr/rev = (L/hr)/(rev/hr) mL/rev = L/rev * 1000mL/L
August 18, 2015

calculus
min/max occur where y'=0 So, just solve 4x^3-12x^2+8x=0 So, which are min and which max? Minimum if y" > 0 (concave up) Maximum if y" < 0 (concave down) So, take a look at y" = 4(3x^2-6x+2)
August 18, 2015

math 5
I didn't see a question, but your response seems like a reasonable answer.
August 18, 2015

Math
R=xxx clearly the 1st digit is 0 or 5, so it must be 5, since 3-digit numbers don't usually start with 0. R=1x5 The second and third digits add to 8 R=135 The last item is redundant.
August 18, 2015

maths - incomplete
did you forget the interest rate? The principal?
August 17, 2015

Algebra
That would be ∜(8/9a^3) Not sure what you mean by simplify. You could break it into separate factors, but There aren't any 4th-powers to factor out of the radical.
August 17, 2015

math
The angles are 5x,6x,7x and they add to 180. So, 18x = 180, x=10, and the angles are 50,60,70 So what do you think?
August 17, 2015

math
check your distance formula. It is √((5-(-3))^2+(-5-1)^2) = √(8^2+6^2) = √100 = 10
August 17, 2015

math grade 12
.75 * .75
August 17, 2015

math grade 12
Add up all the points. You need x where 85+89+x >= 3*90
August 17, 2015

Math
much better!
August 17, 2015

Math
How ever did you come up with that answer? You have 5a, and you want a by itself. How do you get rid of the 5? Recall that 5/5 = 1
August 17, 2015

Math using symbols
you are correct on both of them. Good work.
August 17, 2015

Math using symbols
you have 2 rows, each with 3+4 stars So, what do you think? Hint: distributive property In #2, there is no multiplication, just 3+4+5 stars So, what do you think? Hint: associative property
August 17, 2015

Math
Nope. Inequalities do not have a single value for a solution. -3 < 2x+1 < 5 -4 < 2x < 4 -2 < x < 2 Clearly 4 does not work. 2*4+1 is not less than 5. Any value between -2 and 2 will work.
August 17, 2015

Math
so am I. All I can do is use what you wrote, which doesn't make a lot of sense to me. How about you try posting the real question? |1| = 1 |11| = 11 Other than that, I have no help to give at this point.
August 17, 2015

Math
That would be _____+10
August 17, 2015

algebra 2
If you are trying to find the determinant such that |0 0 -1| |3 x 0| = x^2 |2 0 3| Then that reduces to 2x = x^2
August 17, 2015

math help
It is C if you meant 5*2x^2 Try not to confuse x (the variable) with x (multiplication) Use * to multiply ^ for powers
August 17, 2015

Algebra
domain is all reals except where the denominator is zero So, if you have 1/(x-1)^2 - 5 D= all reals except x=1 Clearly, 1/(x-1)^2 is smallest when x is huge. Then it is close to zero, but always a little bit positive. So, R= all reals y > -5
August 17, 2015

Algebra
If there are x vials of A, then then the rest (60-x) are of B. So, adding up the costs, we have 39.95x + 30.34(60-x) = 2022.21 Now just solve for x and then figure 60-x.
August 17, 2015

kogi state university
If there are n to choose from, then that is P(n,5) or C(n,5)
August 17, 2015

math
168 @ 43.5° = <115.6,121.9> 33 @ 133.5° = <23.94,-22.72> add up the x- and y-components and the resultant velocity is <139.54,99.18> = 171.20 @ 54.6°
August 17, 2015

chemistry
assuming STP for the O2, you have 5.6/22.4 = 0.25 moles O2 5.6g = 5.6/55.85 = 0.10 moles Fe If your reaction is 4Fe + 3O2 = 2Fe2O3 then the reaction consumes elements in the ratio (moles O2)/(moles Fe) = 3/4 Your available reagents are in the ratio of O2/Fe = 0.25/0.10 = 5/2 ...
August 17, 2015

mathematics
I cannot interpret all those words. What is "by" supposed to mean? Is 3 to power 5by2 2*3^5 or (3^5)^2 That is, does by mean multiply by or raise to a new power? Try using * for multiply ^ for exponent () to make it clear what is grouped Ahhh. I think the "by&...
August 17, 2015

uniuyo
the 5th terms is the 3rd after the 2nd term, so their ratio is r^3. Thus, r^3 = 567/21 = 27 r = 3 a = 21/3 = 7
August 17, 2015

word problem
x+y = 38 8+2x = 5y Now just solve for x and y
August 17, 2015

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