Saturday

December 3, 2016
Total # Posts: 46,781

**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*

**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*

**maths**

(11+x)(8+x) = 208 x^2 + 19x + 88 = 208 x^2 + 19x - 120 = 0 (x+24)(x-5) = 0 In 5 years they will be 13 and 16 check: 13*16 = 208

*November 26, 2016*

**math**

If the 3rd number is x, then 2x + 2x+1 + x = 33

*November 26, 2016*

**Math**

clearly 4+10 ? 40 (though, 4*10=40) x-6 + x = 40 x = 17 17+23 = 40

*November 26, 2016*

**Math**

not sure what the Arabic says, but log 1/32 = -log32

*November 26, 2016*

**hdhs**

(10+.1)(9+.1)(2.5+.1) - 10*9*2.5 = 13.966 cm^3

*November 26, 2016*

**Calculus**

x ln(1-2y) = z sin((x^2)z)-3y+z x (-2/(1-2y)) = z' sin((x^2)z) + z cos((x^2)z)(x^2 z') - 3 + z' z' = (2x/(2y-1) + 3) ------------------------------------- sin((x^2)z) + x^2z cos((x^2)z) + 1

*November 26, 2016*

**Trigonometry**

I suggest you post the problem exactly as it was given to you. If it's just part of an exercise set, include the instructions that preceded the section containing the problem.

*November 25, 2016*

**Physics**

2.3 kg? That's some pencil!! You sure you did not mean 2.3 g? That's too light. You sure you meant pencil?

*November 25, 2016*

**Trigonometry**

huh? This is a single function! Not sure what you're getting at...

*November 25, 2016*