Saturday

November 22, 2014

November 22, 2014

Total # Posts: 26,888

**English**

yes and yes
*October 3, 2014*

**math**

The size of the cut will not, of course, change the length of the board. It will, of course, affect the total length of the cut pieces, since 1.25" will be lost after 10 cuts. I suspect there is more to this problem than what you asked, but if you want answers, you have ...
*October 3, 2014*

**geometry**

That would be 672 - (-36) = ?
*October 3, 2014*

**math**

If $x go at 2%, the rest (4000-x) is at 5%. So, add up the interest on each part: .02x + .05(4000-x) = 155.00
*October 3, 2014*

**algebra**

If the plane's speed is p, and the wind's speed is w, then since distance = speed * time, 3(p+w) = 1500 3(p-w) = 1380 Now you can easily find p, and then w.
*October 3, 2014*

**Math**

yes.
*October 3, 2014*

**physics**

total distance: 15.9+25.3+34.3 = 75.5 mi total time: 15.9/51 + 25.3/41 + 34.3/38.6 = 1.82 hr So, avg speed is 75.5mi/1.82hr = 41.55 mi/hr
*October 3, 2014*

**Math**

no - that fixed fee of $32 wrecks the proportion.
*October 3, 2014*

**Math**

First, the income in 2010 is not P(10), it is P(3). P(t) is only defined for 2<t<6, where t is the years since 2007. P(3) = 6(3)-24 = -6, so P(t) is decreasing there. Note that P'(t)=0 when t=4. That means it is decreasing more slowly until t=4, then starts to ...
*October 2, 2014*

**Calculus**

You have the right idea, but y' = 1 - 1/(2√x) Setting that to zero, we get 1 - 1/(2√x) = 0 1/(2√x) = 1 2√x = 1 √x = 1/2 x = 1/4 As you can see from the graph, there is only the one point (1/4,-1/4) with a horizontal tangent. http://www....
*October 2, 2014*

**Math**

Do you know what the midpoint is? It is the point midway between A and C. That is, it is the same distance from A as it is from C. That is, AB = BC
*October 2, 2014*

**Calc**

both wrong. Better review the definition of continuous. sin(x)/x -> 1 as a limit as x->0, but 0/0 is not defined, so it is not continuous there.
*October 2, 2014*

**Math**

p = (74.5+124.2)/242 p is not 1.0, because of things called divorce and death.
*October 2, 2014*

**physics**

since the distance s = vt + 1/2 at^2, 4780*525 + 525^2/2 ax = 3.54*10^6 8850*525 + 525^2/2 ay = 7.77*10^6
*October 2, 2014*

**math**

For F(x,y) = 3y cosx, we have Fx = -3y sinx Fy = 3 cosx Fxx = -3y cosx Fyy = 0 Fxy = -3 sinx So, for a saddle point, we need Fx = 0 true for x=0,pi or y=0 Fy = 0 true for x=pi/2, 3pi/2 and all y Fxx * Fyy - (Fxy)^2 < 0 -3y cosx * 0 - (-3 sinx)^2 < 0 true for all x. The ...
*October 2, 2014*

**pre calculus**

since d/F is constant, .15/265 = .2/x and, .165/265 = x/100 Note that you don't really have to find k, the constant of proportionality. You can go ahead and find it, but your answers will be the same.
*October 2, 2014*

**math**

approximate: use 30 days per month. exact: get a calendar.
*October 2, 2014*

**Math**

At x=2, x-5 < 0, so the slope at x=2 is just -1. Ok, ok, algebraically, f(2+h) = |2+h-5|-7 = |-3+h|-7 Since the value is negative, that will be 3-h-7 = -4-h f(2) = |2-5|-7 = 3-7 = -4 -4-h - (-4) = -h Now, divide by h and you have -h/h = -1
*October 2, 2014*

**Math**

pretty good, but you know that cot π/4 = 1 csc π/4 = √2, so m = -12(1)(2) = -24 So the line is y-3 = -24(x-π/4)
*October 2, 2014*

**geometry**

If the points are in a aline, then I expect AB + BC = Ac So, 9a + 12a = 42 21a = 42 a = 2 Now you can figure out the lengths AB and BC
*October 2, 2014*

**Math (Implicit Differention)**

of course, you can simplify that last result to just √3, since it is (3^(3/2))^(1/3) = 3^(1/2) Also, you dropped/gained a minus sign in there somewhere. The point is in QII, where the slope is positive.
*October 2, 2014*

**calculus**

x^2/3+y^2/3=4 2/3 x^-1/3 + 2/3 y^-1/3 y' = 0 y' = -(y/x)^1/3 So, at (-1,3√3), y' = -(3√3/-1)^(1/3) = √3 You can see the graphs at http://www.wolframalpha.com/input/?i=plot++x^%282%2F3%29%2By^%282%2F3%29%3D4+%2C+y+%3D+-%E2%88%9A3%28x-1%29+%2B+3%E2%...
*October 2, 2014*

**Math - Please Check My Answer - Probably Last One!**

the ratio is just (πr^2h) / (2r)^2*h πr^2h / 4r^2h π/4
*October 2, 2014*

**Math - Please Check My Answer**

D is correct. In A, 3x^0 = 3*1 = 3, while (3x)^0 = 1 (assuming x is not zero)
*October 2, 2014*

**AC DC Circuit fundamentals**

since they are in series, the voltage drop is divided up into 2/3 across the 10k 1/3 across the 5k since R = R1+R2 = 5+10 = 15 k, and 10 is 2/3 of 15, 5 is 1/3 of 15.
*October 2, 2014*

**Trigonometry**

f(x-a) is f(x) shifted right by a. So, yours is shifted left by 5. f(x)+k is f(k) shifted up by k.
*October 2, 2014*

**Math**

4(x+15) >= 120 x+15 >= 30 x >= 15
*October 2, 2014*

**Math**

3/2 + 23 since max of sine is 1.
*October 2, 2014*

**Math**

right again.
*October 2, 2014*

**Math**

both correct!
*October 2, 2014*

**Trigonometry**

since the maximum of sin(x) is 1, d(t) achieves a maximum of 3/2 + 23.
*October 2, 2014*

**Math**

Just do hex long division, as at http://mathforum.org/library/drmath/view/63375.html However, it is sometimes easier to convert to decimal, divide, and convert back.
*October 2, 2014*

**Algebra ll**

division by zero is not defined. What is 12/0? 0/0? So, for a rational function, the domain excludes any values where the denominator is zero, because the domain is the set of values of x for which f(x) is defined. For f(x) = (x^2 - 25)/2 the domain is all real numbers; there ...
*October 2, 2014*

**Simplify this Expression?**

You can do it using the distributive property as J and Ms Sue did, or you can use it implicitly, working term by term z-2z+4z+6 -z+4z+6 3z+6 Their answers basically factored out the z, as in z-2z+4z+6 (1-2+4)z+6 (3)z+6 3z+6
*October 2, 2014*

**geometry**

think of alternate interior angles, or consecutive interior angles.
*October 2, 2014*

**Trigonometry**

Just do things as you normally would. tan 28 = 0.5317, so you have (20-x)/6.11 = 0.5317 20-x = 3.25 x = 16.75 Don't forget your algebra I just because you're taking trig now!
*October 2, 2014*

**math**

Looks to me like .013
*October 2, 2014*

**Plane and Spherical Trigonometry**

Use the law of cosines. The third side can be found using AC^2 = 20^2 + 35^2 - 2(20)(35)cos(180-80)°
*October 2, 2014*

**math**

(g-48)(g-20) = 480 g = 60 So, the grandfather is 60. ...
*October 2, 2014*

**Math**

1/4 * 1/2 = 1/8
*October 2, 2014*

**math**

(14 - (15/3))/2 = 9/2
*October 2, 2014*

**English - Parts of Speech**

a simple google search will provide numerous examples.
*October 2, 2014*

**maths**

sorry, no diagrams here. But I bet you can do it. Just look in your text (or online) for similar situations, and change the numbers. You just have to draw two intersecting circles.
*October 2, 2014*

**algebra**

7 + 2x
*October 2, 2014*

**Physics**

A 0.60-kg basketball is dropped out of the window that is 6.1 m above the ground. The ball is caught by a person whose hands are 1.2 m above the ground. (a) How much work is done on the ball by its weight? (b) What is the gravitational potential energy of the basketball, ...
*October 2, 2014*

**Physics**

The drawing shows two boxes resting on frictionless ramps. One box is relatively light and sits on a steep ramp. The other box is heavier and rests on a ramp that is less steep. The boxes are released from rest at A and allowed to slide down the ramps. The two boxes have ...
*October 2, 2014*

**Math**

as with all fractions, multiply top and bottom by the GCD (a-1)(b) to get 1/(a-1) + 1/b = c b + (a-1) = c(a-1)(b) b + a - 1 = abc - bc a - abc = 1 - b - bc a = (1-b-bc)/(1-bc) = 1 + b/(bc-1)
*October 1, 2014*

**Precalculus**

If the width surrounding the rug is w, then (12-2w)(16-2w) = 12*16/2 Now just solve for w and determine the rug dimensions.
*October 1, 2014*

**calculus**

The curves intersect at (4,0) and (1,3). You don't specify the axis, so, assuming the x-axis, using shells, the volume is v = ∫[0,3] 2πrh dy where r = y and h = (5-(y-1)^2)-(4-y) v = 2π∫[0,3] 3y^2 - y^3 dy = 27π/2 Using washers, we have to break ...
*October 1, 2014*

**Algebra HELP!**

No ideas on any of them? Look for groupings of like expressions, difference of two squares, etc. For example, (g) is (x^2-y^2) + x + y (x-y)(x+y) + (x+y) (x-y+1)(x+y)
*October 1, 2014*

**Algebra**

Looks good to me. I tend to avoid fractions where possible, so I'd probably have done it as 42+48+x = 3*47
*October 1, 2014*

**Math**

(6+2w)(12+2w) = 520 w = 7
*October 1, 2014*

**Math help!**

(-2)^n+2n: -2+2, 4+4, -8+6, 16+8, ... n^2(-1)^n: -1, +4, -9, ... |10-n^2|: |10-1|, |10-4|, |10-9|, ...
*October 1, 2014*

**Math**

nope - that fixed fee of $32 wrecks the proportion.
*October 1, 2014*

**Math**

the length is clearly 36 cm The pieces can be (36/9)x26 or 36x(26/9) Assuming you want integer dimensions, I'd go with the first choice.
*October 1, 2014*

**Math**

68*3 + x = 70*4 you want large on top and small on bottom, so 984/12
*October 1, 2014*

**Algebra**

what, you have a problem evaluating expressions? (-2)^n+2n: -2+2, 4+4, -8+6, 16+8, ... n^2(-1)^n: -1, +4, -9, ... |10-n^2|: |10-1|, |10-4|, |10-9|, ...
*October 1, 2014*

**algebra2/ trig**

The centers of the pipes form an equilateral triangle, with sides of length 24. The belt then consists of three straight segments of length 24, and three arcs of the circles, subtending angles of 2pi/3.
*October 1, 2014*

**algerbra 1**

Strange language; I suspect you meany "by" 15, so on that basis, we have 2x = 3(x+4)+15 -x = 27 x = -27 and the numbers are -27 -25 -23 check: -54 = -69+15
*October 1, 2014*

**Math**

yes - just divide as shown 7/3 = 2.33 3/4 = 0.75 and so on
*October 1, 2014*

**Math**

#1 ok #2 - the discount was 15%, meaning the actual price was 85%, so 0.85p = p – 150 #3 WHAT? They just told you that A traveled 22 mph faster than B! If car B has speed s, then 2.4(s+22) = 4s This will give you B's speed. The distance traveled was 4s #4 If the ...
*October 1, 2014*

**Math help!**

clearly, at a change rate of -20 per year, (a) -20(5) = -100 (b) -20(-5) = +100 (c) -20n (d) -20(-n) = +20n
*October 1, 2014*

**Trig**

The first plane ends up at (169.7,-169.7) The other plane ends up at (-205.1,-205.1) So, relative to the first, the second plane is at (-374.8,-35.4) arctan(-35.4/-374.8) = 185.4°, or W5.4°S
*October 1, 2014*

**Chemistry/Math**

ppm of what? .01403g is just a mass. That's not much to go on
*October 1, 2014*

**Algebra**

just write each sentence in symbols, then solve the equations. #1 Maria has 105+10m Jana has 0 + 25m So, we want 105+10m = 0 + 25m Now just solve for m and then the amounts #2 There's a rental rate of r, and a late fee of f, so Nate: r + 1f = 5.50 Gina: r + 4f = 10.00 Now ...
*October 1, 2014*

**Math-G7 Help please**

#1 d = b+4 d+b = 22 #5 w(x+y) = 126 y = 2x #8 d+q = 20 10d+25q = 275 #15 s+a = 421 2s+5a = 1244 #17 b = s/3 b+2s = 84 Just translate each sentence into symbols.
*October 1, 2014*

**Math**

4(0) + 1(-3) + 1(-6) + 4x = 63 Now just solve for x
*October 1, 2014*

**math**

change in speed = 8 m/s at 2(m/s)/s, that will take 8/2 = 4 seconds
*October 1, 2014*

**Algerbra math**

(7+2)x^2 + (3+5)x + (9-2) That should help.
*October 1, 2014*

**Math**

any number bigger than the square root of Dalton's area.
*October 1, 2014*

**math**

to find y(x) for a specific x, just replace each x with its value. (a) y(-1) = -3(-1)-2 = 3-2 = 1 and so on (d) -a = -1(a) (e) just solve for x in -3x-2 = -11
*October 1, 2014*

**College algebra**

if there were x reserved seats, then the rest (40000-x) were general admission. So, adding up all the ticket prices, we get 12x + 5(40000-x) = 298000 x = 14000
*October 1, 2014*

**Math- Multi-step word problems**

3(s+20) = 3.20(s-20) s = 620 3*640 = 1920 3840/(3 + 3.20) = 619.35 so you are correct
*October 1, 2014*

**Math- Multi-step word problems**

d/(10-3) = d/(10+3)+1 so you are correct
*October 1, 2014*

**Math- Multi-step word problems**

If the plane's speed is s, then since distance = speed * time, 4(s+10) = 4.15(s-10) That gives s=543.33 553.33*4 = 2213 533.33*4.15 = 2213
*October 1, 2014*

**Math--1 question**

well, you can surely see that 56+c = 83 It's easy to find c, and it's not 33.
*October 1, 2014*

**Trigonometry**

Draw another line making an angle of 28°, passing through the tip of the overhang to the wall. If the height of sunlight on the wall is x, then (20-x)/6.11 = tan 28°
*October 1, 2014*

**math**

that depends on the tools you have at your disposal. Some curves have special properties, like the vertex of the parabola ax^2+bx+c is at x = -b/2a, and so forth. If you have access to calculus, you can find minima on a wider variety of curves. The most general tool would be a...
*October 1, 2014*

**math**

45(.80 - 1/3) = 21 The tank was not full at the beginning of the month, but only 80% full, or 36 gallons.
*October 1, 2014*

**Maths**

693 = 3^2 7 11 1365 = 3 5 7 13 The highest powers of all the primes in both lists are 3 7 so the GCF is 21
*October 1, 2014*

**Math Multiplication**

Just start trying divisors: 1 642 2 321 3 214 6 107 Since 642 = 2*3*107, that is all the factors there are
*October 1, 2014*

**math**

old diameter: d old area: pi/4 d^2 new diameter: 1.5d new area: pi/4(1.5d)^2 = pi/4 d^2 (2.25) So, new area - old area = 2.25-1 = 1.25 = 125%
*October 1, 2014*

**math**

hmmm. Looks like (54.28 - 48.70)/2 = 2.79 inches why the /2 ?
*October 1, 2014*

**Trigonometry**

as usual, amplitude = 1/2 period = 2π/π = 2 The - sign doesn't mean anything here, since cos(-x) = cos(x)
*October 1, 2014*

**Trigonometry**

C'mon. If 2π/k = .004, k = 2π/.004 = 500π
*October 1, 2014*

**Trigonometry**

this is just the other problem in reverse. Why not give it a shot? You know that the period of sin(kx) is 2π/k... Also, period = 1/frequency
*October 1, 2014*

**Trigonometry**

amplitude = 3 period = 2π/1 = 2π
*October 1, 2014*

**math**

Just looking at the formula, you could surely see that 10 is wrong, because then the area would be 100π = 314, not 658. So, πr^2 = 658 r^2 = 658/π = 209.4479 r = 14.47
*October 1, 2014*

**physics**

If the boat's speed is s, and the river's speed is r, and the boat is traveling east (0 degrees), (0,r) + (s cos297,s sin297) = (6,0) now just solve for r and s.
*October 1, 2014*

**math**

(6x^3+13x^2+6x+158)/(3x+11) = 2x^2-3x+13 R 15 If that was supposed to come out even, I suspect a typo. I guess you will have to figure out why NCC is important.
*October 1, 2014*

**Pre-Calculus/Trig...**

Surely you can graph both those simple functions. Just switch from one to the other at x=1. since 0 < 1, f(0) x^2 = 0.
*October 1, 2014*

**College Alg**

P(x) = R(x)-C(x), so just solve for x in x(50-.002x) - (12x+150000) = 1650000 I suspect a typo, since that has no real solutions.
*October 1, 2014*

**slopes**

actually, you mean the line joining the two points. well, starting at (4,9), how much do x and y change getting to (2,9)? y does not change, so the slope is zero.
*October 1, 2014*

**Basic programming principles**

incorrect
*October 1, 2014*

**Basic programming principles**

First, let's add some parentheses to indicate order of operation: ((A * 3 >= B – 14 \ 3)AND(F)) OR (C <= D+3) Now, anything AND FALSE is FALSE, so we are left with FALSE OR (12 <= -4+3) FALSE OR FALSE FALSE
*October 1, 2014*

**Basic programming principles**

well, is 4+20 <> (4+17)*4 ? Looks true to me.
*October 1, 2014*

**chaitanya**

measuring from the first point, s(t) = vt + 1/2 at^2 we know that s(6) = 180, so 6v + 18a = 180 Also, we have v + 6a = 45 So, v=15 and a = 5
*October 1, 2014*

**physics**

The boat and its contents are floating, so its general density is less than that of water. So, the boat displaces a volume of water which has the same mass as the boat. But a rock is denser, so it displaces less water. SO, the amount of water displaced drops when the rock ...
*October 1, 2014*

**math**

d and e are obviously out, since they do not start with 3. Of the others, which has terms that increase by 2?
*October 1, 2014*

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