Sunday
December 4, 2016

Posts by steve

Total # Posts: 46,790

precalculs
just substitute y = 2x+2 into the first equation. You know a line intersects a parabola in at most two places.
November 29, 2016

precalculus
x = -y, so x^3 - 5x + x = 0 x^3-4x = 0 ...
November 29, 2016

precalculus
come on. This is Algebra I. What do you think is the answer? If nothing else, just plug in the values and see where they fit!
November 29, 2016

math
sure you do. Did you not read where it said Therefore, each factor equals 91? 3x-2 = 91 3x = 93 x = 31 It's hard to solve a problem if you don't read it!
November 29, 2016

Vectors and matrices
what's to do? Just draw the triangles. They even gave you the coordinates! Just to make sure they weren't lying, do the math: http://www.wolframalpha.com/input/?i=%7B%7B3,-1%7D,%7B5,-1%7D,%7B5,-4%7D%7D*%7B%7B1,0%7D,%7B0,-1%7D%7D
November 29, 2016

algebra
ever hear of y = mx+b It's called the "slope-intercept" form for a reason.
November 29, 2016

Algebra
well, if x is the number, what is 1/4 of the number? ...
November 29, 2016

physics
since each part has the same mass, conserving momentum is just conserving velocity: <0,8> + <-8,0> + <x,y> = 0 or, since the resultant momentum of the two known parts is NW, the 3rd part must go SE.
November 29, 2016

linear equations
reposting the same thing wastes everyone's time.
November 29, 2016

math
L = 2W 2(L+W):6L = 1:2 L+W/3L = 1/2 (2W+W)/(3*2W) = 1/2 3W/6W = 1/2 3/6 = 1/2 This is true for any value of W! I suspect the question has been mangled.
November 29, 2016

Maths quadratic equation
see related questions below
November 29, 2016

Math
google is your friend. You might want to start here: https://answers.yahoo.com/question/index?qid=20080427160136AACsLX6
November 29, 2016

Math
#1 has a typo you provide no pairs for 2,3,4,5 For #6, you know that x = y+3 So, y = x-3 I assume one of the graphs works for that. For the rest, work to isolate the variable #7 -4 = g+1 you want g all alone, so get rid of the 1 with subtraction -4-1 = g+1-1 -5 = g the others ...
November 29, 2016

Math
surely you can come up with something, at least to start with ...
November 29, 2016

math
I answered this when you were "somay" http://www.jiskha.com/display.cgi?id=1480393573
November 29, 2016

Math (Calculus) (Related Rates)
as we saw earlier, the distance z is z^2 = 1+x^2 z dz/dt = x dx/dt plugging in the numbers, z(3) = ?10, so ?10 dz/dt = 3 * 2 dz/dt = 6/?10 = 1.897 So, I guess you were right on that one. As for dz/dt when x gets large, consider that z^2 = 1+x^2 as x gets large, that is just z^...
November 29, 2016

Science
42
November 29, 2016

math
This one is really quite simple, if you understand what the mean and mode are. The mode is the most frequent score. Since there are only three scores, and the mode is 11, it must occur more than any other score. That is, 11 occurs twice. Since the mean is 9, the sum of the ...
November 28, 2016

math
that would be 5
November 28, 2016

math
the slope is the rate of sales, in cars/month. So, just use the numbers given: 13cars/3months = 13/3 cars/month The slope is 13/3
November 28, 2016

MATH
flour:sugar = (3/4):(3/5) = 5:4 so, a kg of flour costs 4/5 as much as a kg of sugar. That is, 5 kg of flour costs the same as 4 kg of sugar. So, the 4 kg of sugar cost half of the $14.80. That means a kg of sugar costs $3.70
November 28, 2016

math
since 9 and 4 are both perfect squares, try (3x-2)(3x-2).
November 28, 2016

Math
hint: 15-2 = 13
November 28, 2016

Math
yes. Since both points have 4 for a y-coordinate, the line is horizontal: y = 4
November 28, 2016

Math
x would represent a number. The width is twice the height. so, 2*3(x/3+5) = 90
November 28, 2016

algebra
guess again. 2*2-1 = 3 not -1 clearly you did not test your choice.
November 28, 2016

Math (Calculus) (Related Rates)
oops. I meant find dz/dt.
November 28, 2016

Math (Calculus) (Related Rates)
at a distance x, the length of rope (z) is z^2 = x^2+1 now just find dz/dx at x=3 it should be clear how z changes when x is large.
November 28, 2016

Math
.18x = 11800 love your capitalization and punctuation and spelling. <not>
November 28, 2016

maths
x + x+4 + 3x = 44
November 28, 2016

Math (please check my answer!!)
Nope. SSA does not work.
November 28, 2016

math
well, certainly both numbers must not exceed 20. So, how many pairs x,y with x,y <= 20 fit that?
November 28, 2016

Math
suppose I asked you to find w such that 50 = 5w what would you do? Divide by 5, right? So, divide by L: W = A/L
November 28, 2016

math
T10 = a+9d = 40 S10 = 10/2 (a+40) = 265 a = 13 so, d=3 S20 = 20/2 (2*13+19*3) = 830
November 28, 2016

math
what are the perfect squares less than 12?
November 28, 2016

Maths
7sin^2x - sinx cosx - 6 = 0 divide by cos^2 to get 7tan^2x - tanx - 6sec^2x = 0 7tan^2x - tanx - 6(1+tan^2x) = 0 tan^2x - tanx - 6 = 0 there's a typo, and any solutions must exclude x where cosx=0.
November 28, 2016

Math
both do, since there are no constants involved.
November 28, 2016

Math
If z>=0, 2+z > 1 -- z > -1 2-z <= -1 -- z >= 3 If z<0, 2-z > 1 -- z < 1 2+z <= -1 -- z <= -3 graph those on the number line, and you will find your answer. Be sure to check a few values to make sure they work, especially at the boundaries.
November 28, 2016

emt
?[0,1]?[0,1] (x^2+y^2+25)^(3/2) dx dy = 130.046 This is not a trivial task, since it involves trig substitutions. Anyway, look here to find the first indefinite integral. Plug in your two y-values, giving a similar integral involving only x. http://www.wolframalpha.com/input/?...
November 28, 2016

Math
42.42
November 28, 2016

Algebra
Clearly she must add 5 liters. So, to get the concentration, .14*2 + x*5 = .34*7 ...
November 28, 2016

Business Math
Hmmm. Too bad you didn't show your work... revenue = price * quantity. breakeven is when cost = revenue, so 3600+100x+2x^2 = x(500-2x) x = 10,90 maximum profit will be at the vertex of p = r-c, halfway between the roots: x=50
November 27, 2016

inverses
I don't mean the formula. I mean, in the original problem, what was the variable x defined to be? Answer that, and you have answered your problem.
November 27, 2016

inverses
well, what does x represent?
November 27, 2016

history
This is my last question Describe some of the achievements of the Middle Kingdom of ancient Egypt.
November 27, 2016

history
What does Herodotus question about the Nile in this quote? why it has its great floods why it has no breezes blowing from it why it has its towering forests why it has its enormous length I need help bad plz. I have tried looking in my text book and everything.
November 27, 2016

history
Ms. sue I am so dumb SHOuld've read it lol
November 27, 2016

history
What lands beside Egypt does the Nile flood? Mesopotamia Ethiopia Libya and Arabia Narmer
November 27, 2016

runways and inverses!
looks good to me.
November 27, 2016

dp
recall the definition of pressure = force/area
November 27, 2016

Algebra
n = 2d+1 now add up the values, and then solve for n and d.
November 27, 2016

Math
treat these just like any other binomial, keeping reals and imaginaries separate: -i-2-(6-4i)-(5-2i) -i-2-6+4i-5+2i (-2-6-5)+(-1+4+2)i -13+5i
November 27, 2016

math
If the number of seats for the categories is x,y,z then just list the data: x = 9z x = 55+y+z 15x+24y+41z = 46152 Now just solve for x,y,z
November 27, 2016

Algebra
Since distance = speed * time, 70t + 25 = 60(t + 1/2) t = 1/2 So, 70mi/hr for 1/2 hr = 35mi 60mi/hr for 1 hr = 60mi = 35+25 mi
November 27, 2016

Math algebra
f^-1 = (x+1)/2 check: f^-1(f) = (f+1)/2 = (2x-1+1)/2 = x f(f^-1) = 2f^-1 - 1 = 2(x+1)/2 - 1 = x
November 27, 2016

Math
total students: 545 Now, a whole circle is 360°, so 190/545 * 360 = 125.5° and similarly for the other angles.
November 27, 2016

pre calculus
i = 1 cis ?/2 ?i = ?1 cis ?/8 this is very straightforward, a direct application of the formula.
November 27, 2016

precalculus
r^2 = x^2+y^2 tan? = y/x same as with polar coordinates.
November 27, 2016

Math algebra
d = ks^2 So, d/s^2 = k, a constant. So, you want d such that d/56^2 = 60/40^2
November 27, 2016

Math algebra
A = k*R1*R2/L^2 "exponents" at the bottom are called subscripts.
November 27, 2016

precalcalculus
if given two angles, use A+B+C=180° Then, if only one side, use law of sines If three sides, use law of cosines to find an angle. If only one angle, use law of sines to get a 2nd one. Then see step 1.
November 27, 2016

Maths, multiplicative inverse
-3 = 23 (mod 26) 17*23 = 26*15 + 1
November 27, 2016

Math
6yd * 4yd = 24 yd^2
November 27, 2016

Math
convert each vector to x-y form add the components convert back to polar
November 27, 2016

Math
48 is 2 less than 50 50-x is x less than 50 thrice a number less than fifty is 50-3x 7 less than a number is x-7
November 27, 2016

Maths
the turning points are in between the x-intercepts.
November 27, 2016

Trigonometry
arctan(cot(x)) = arctan(tan(pi/2-x)) = pi/2-x This is not quite true when dealing with QIII angles...
November 27, 2016

math
x = kuv/(u+v) when you come up with a question, this should help answer it.
November 27, 2016

math
D = ks
November 27, 2016

math
the linear scale is 1:5 so, the areas are in the ratio 1:25
November 27, 2016

Maths
same as angle D
November 26, 2016

Calculus
Consider the triangle at distance x. Its base is 2y, and its height is y?3. So, adding up the volumes of all those triangles of thickness dx, we have (applying symmetry) v = 2?[0,3] 1/2 * 2y * y?3 dx = 2?3 ?[0,3] y^2 dx = 2?3 ?[0,3] (9-x^2) dx = 36?3
November 26, 2016

Math
http://www.wolframalpha.com/input/?i=93log(d)%2B65+for+d%3E0 Note that it's just the usual log graph, shifted up and scaled.
November 26, 2016

pre calculus
(x^2-25?i)(x^2+25?i) (x-5?i)(x+5?i)(x-5?i i)(x+5?i i) Now just use de Moivre's formulas to find ?i. If you want, you can rephrase these solutions as ±5(-1)^(1/8) ±5(-1)^(5/8)
November 26, 2016

Calculus
using cylinders, we have v = ?[1,3] 2?rh dy where r=5-y and h=x=(y-1)^2 ?[1,3] 2?(5-y)(y-1)^2 dy = 40?/3
November 26, 2016

Calculus
draw the region. Using discs (washers), the volume is v = ?[0,4] ?(R^2-r^2) dx where R = 5-y and r = 5-3=2 v = ?[0,4] ?((5-(1+?x))^2-(2)^2) dx = 40?/3
November 26, 2016

calculus
at time t hours, the distance z is z^2 = (40-20t)^2 + (30t)^2 now just find when dz/dt = 0
November 26, 2016

precalculus
w = <4,1> - <-8,12> = <12,13> now just convert to polar form.
November 26, 2016

Math
2/3 = 8/12 so, if he ate 6/12, ...
November 26, 2016

Math
assuming the house is clean when Mimi gets home, consider that in one hour, 1/5 - 1/7 = 2/35 of the house gets messed up each hour.
November 26, 2016

Math
Assuming typos, 1/3 of the fish found in February were tagged. So, 180 represents 1/3 of the fish in the lake.
November 26, 2016

Algebra 2
Bzzt. But thanks for playing... two imaginary solutions means the discriminant is negative: 36-4c < 0 c > 9
November 26, 2016

Algebra 2
9 = 3^2, so it's (b) which you could have verified by actually doing the multiplication, guy.
November 26, 2016

pre calculus
these are all the same. You must have some of your own work to show by now.
November 26, 2016

pre calculus
w = <4,1> - <-8,-12> = <12,13> Now just convert back to polar form.
November 26, 2016

pre calculus
pick any angle (say, A) and find it via a^2 = b^2 + c^2 - 2bc cosA Now the area is given by 1/2 bc sinA
November 26, 2016

physics
so, what is the formula for centripetal acceleration? Just plug in your numbers to find ?.
November 26, 2016

Math
Since the degrees have equal size, (29-21)/(21+273.15) * 100 = 2.7%
November 26, 2016

math
20% of the sum of their original prices, because of the distributive property.
November 26, 2016

pre calculus
try getting the notation right: e^(a+bi) = e^a (cosb + i sinb) Now just plug in a=0, b=?
November 26, 2016

calculus
just integrate each component. 0 to 1800 seconds.
November 26, 2016

Differential calculus
since h = (10/4) r, v = pi/3 r^2 (10/4 r) = 5pi/6 r^3 now differentiate and solve for dr/dt
November 26, 2016

Calculus
dz/dy = x e^(xy) + 2cos(xy-1) - 2xy sin(xy-1)
November 26, 2016

Differential calculus
x^2+y^2 = 20^2 now take derivatives and solve for dx/dt
November 26, 2016

Calculus
df/dx = e^-x (x^2-2x+y^2) df/dy = 2e^-x y both are zero only at (0,0)
November 26, 2016

Differential calculus
using similar triangles, when the man is x feet from the building, s/30 = 6/(30-x) 1/30 ds/dt = -6/(30-x)^2 dx/dt Now just plug in your numbers to find ds/dt
November 26, 2016

Differential calculus
see related questions below
November 26, 2016

Physics
1*sin30 = 2*sin? as for density, review what refractive index means.
November 26, 2016

Science
mass = volume*density
November 26, 2016

math
how many ways to pick a skirt? For each skirt, how many ways to pick a shirt? and so on. Just multiply it all together.
November 26, 2016

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