Monday

December 29, 2014

December 29, 2014

Total # Posts: 27,732

**Math and Finance**

5000(1+.08)^8
*December 28, 2014*

**Math**

d = √((5-1)^2 + (3-0)^2)
*December 28, 2014*

**Math**

as you recall, the slope-intercept form y = mx+b describes a line with slope m and y-intercept b. Surely you see the connection with the question above...
*December 28, 2014*

**math**

the stopping distance for a vehicle moving with speed v and deceleration a is s(t) = vt - 1/2 at^2 Since that is a quadratic function, the QF gives a handy way to solve it. And that's "brakes." Give me a break!
*December 28, 2014*

**geometry**

just use the Pythagorean theorem to find the resultant speed (the hypotenuse of the right triangle) √(130^2+20^2)
*December 27, 2014*

**Math**

4 is half the max displacement period = 8/3 seconds, = 2π/k, so k = 3π/4
*December 27, 2014*

**Math**

No, it is negative because I assumed that at t=0 the point is at its lowest elevation. (As my first sentence stated.) If we had started when the point was level with the circle's center, we'd have sin(kt). If we started with the point at its maximum height, then we'...
*December 27, 2014*

**Math**

If the point in question is at the lowest height at t=0 minutes, then y = -cos(kt) diameter is 6, so the radius is 3 y = -3cos(kt) the lowest point is 6" = 0.5 ft, so the axis of the loop is 3.5 ft off the ground: y = 3.5 - 3cos(kt) Since cos(kt) has period 2π/k = 1/...
*December 27, 2014*

**^Maths^**

You could just do the subtraction in base 6 and then convert the answer to base 7: 451-301 = 150 1506 = 1237
*December 27, 2014*

**math**

or, 4 3/8 inches :-)
*December 27, 2014*

**English**

a bit less than average in height. If the average height for men is 5'8", then someone who is 5'4" could be said to be a little on the short side. Similarly, a man 6'0" might be called a little on the tall side. A guy 6'8" is a long tall ...
*December 27, 2014*

**math**

Damon is correct. Surely you can see that 48:80 is not correct. There are only 80 records in all. 48:80 is the correct ratio, but the wrong total. For every 3 new there are 5 hot. So, 3:5 requires 8 records. There are 80 records. 80/8 = 10, so there are 10 sets of 3:5, or 30:...
*December 27, 2014*

**algebra (motion)**

if B takes x minutes, then the two runners cover the entire track in 15 minutes. 1/40 + 1/x = 1/15
*December 27, 2014*

**maths**

-5+20-8 = ?
*December 27, 2014*

**algebra**

almost anything 3/5 4/6 123/125 932789238/932789240 In fact, anything except 1/3 2/4
*December 27, 2014*

**Math**

or, A :-)
*December 26, 2014*

**Math**

The initial position (at t=0) is not -1/2 Or is that initial - just a separator? Also, if you're going to use parentheses, it ought to be d = 1/2 sin(pi/2 t) - 1/2
*December 26, 2014*

**Math**

If the line does not pass through the origin, it it not proportional. you clearly have y = 25x + 50 That "+ 50" wrecks the proportionality.
*December 26, 2014*

**Algebra**

What you had was 10P4 = 5040 10P6 = 10*9*8*7*6*5 10P4 = 10*9*8*7 So, you can see why 10C6 = 10C4
*December 26, 2014*

**math**

10% ≈ 12, so 60% ≈ 72
*December 26, 2014*

**math**

if it's just one item, I wouldn't call it a total cost. If the customer orders some number of each item, just add up all the item costs to get the total cost. 2c,3s,5d,1j is just a list of costs, not a total. So, how's that English class coming along? ...
*December 26, 2014*

**math**

hint: total cost
*December 26, 2014*

**math**

time = distance/speed, so it takes 1.5x10^11 / 3x10^8 = 0.5x10^3 seconds We all know it takes light about 8 minutes (480 seconds) to reach the earth. .5x10^3 = 500 is pretty close.
*December 26, 2014*

**physics**

three light sources at different directions, maybe of different sizes.
*December 26, 2014*

**statistic**

exactly half. It doesn't matter what the std is. In a normal distribution, 1/2 of the population is above or below the mean.
*December 26, 2014*

**Math**

There are only 3 colors. So, after 6 draws, it is possible to have two of each color. The 7th ball must be the one which matches two of the others.
*December 26, 2014*

**math**

3+4+5+6+7 = 25 So, the milk in the vessels is 3x,4x,5x,6x,7x If the capacity of each is z, then 25x = 0.6*5z = 3z x = 0.12z So, in terms of a full vessel, the amounts of milk in each of the vessels is .36, .48, .60, .72, .84 Looks like 3 of them are over 50% full.
*December 26, 2014*

**Math**

hint: the equation you have shown is called the slope-intercept form of a line. Just read off the slope and the y-intercept...
*December 26, 2014*

**Business Math**

have you no calculator? Heck, just type it into google, if nothing else.
*December 26, 2014*

**science**

the circumference is C = 2pi*r. Make sure your answer is in meters, not cm. Opposite ends of the diameter are half that far apart. Now just multiply that by 12.
*December 26, 2014*

**maths**

you surely have the formula for the surface area of a sphere. Divide that by 4.
*December 26, 2014*

**s.p s**

TODAY (actually, since it's not yet midnight here where I am, there's no way!)
*December 26, 2014*

**Algebra**

F(x) = -3cos(4(x+n/4))+6 So, the amplitude is 3 the period is 2pi/4 = pi/2 the phase shift is -n/4
*December 25, 2014*

**Math**

the period and amplitude do not change, whatever the value of t. The question asks for three things: amplitude frequency distance when t=3 The distance when t=3 is y(3) = -15cos((pi*3)/3)+5 = -15cos(pi)+5 = 15+5 = 20
*December 25, 2014*

**Math**

(a) The period is (2pi) / (pi/3) = 6 so, the frequency is 1/6 your amplitude and distance are correct. Remember, the period for cos(kt) is 2pi/k So, (b) should be no trouble now.
*December 25, 2014*

**math**

Your answers are correct.
*December 25, 2014*

**algebra**

(x-2)(3(x+6)-5(x-3)) (x-2)(3x+18-5x+15) (x-2)(-2x+33) -2x^2+37x-66 or 3(x^2+4x-12)-5(x^2-5x+6) 3x^2+12x-36 -5x^2+25x-30 -2x^2+37x-66
*December 25, 2014*

**precalc**

Suppose the closer point is at distance x. Then you have h/x = tan 20° h/(x+25) = tan 12° eliminate x and you have h/tan20° = h/tan12° - 25 h = 25/(cot12°-cot25°) = 12.774
*December 25, 2014*

**maths**

What atrocious spelling (even for texting!) and grammar. I assume by "my number" you mean "my numerator." If so, then 21/3 = 7
*December 25, 2014*

**Math (PreCalculus)**

If you have no ideas on any of these questions, you seriously need to review your trig functions. y = 5+3sin(πt-π/2) = 5+3sin(π(t-1/2)) (a) at t=0, y = 3sin(-π/2) = -3 Since that is below the equilibrium point, the weight was pulled down. (b) all these ...
*December 25, 2014*

**Math (PreCalculus)**

A spring with a weight attached is oscillating. The weight (which is attached at the bottom of the spring) is 5 feet from a 10-foot ceiling when it’s at rest. The motion of the weight can be described by the equation: y=3sin(pi*t - pi/2) , where y is the distance from the...
*December 25, 2014*

**maths**

By "equal" I assume you mean with the same surface area. So, naturally, each part has 1/4 of the total original surface area.
*December 25, 2014*

**university bahrain**

Probably true. And ? ...
*December 25, 2014*

**binomial**

(x+8y)^5 = x^5 + 5x^4(8y) + 10x^3(8y)^2 + ... = x^5 + 50x^4y + 640x^3y^2 + ... Now just plug in x=1 and y=.01
*December 25, 2014*

**Math (PreCalculus)**

The tip of the second hand travels on a 4" circle, inside a 5" circle. So, at t seconds into the minute, the tip of the second hand is at height 5+4cos(t/60 * 360)° = 5 + 4cos(6t)° from the bottom of the clock.
*December 24, 2014*

**Algebra 1**

if x gallons are 12%, then the rest (20-x) are 7%. So, adding up all the amounts of sugar, you need to solve .12x + .07(20-x) = .10(20) x = 12 You may have worked the problem correctly, but you got your answers switched. Note also that equal amounts of the two would have ...
*December 24, 2014*

**Algebra 1**

A restaurant has one type of lemonade that is 12% sugar and another that is 7% sugar. How many gallons of each type does the restaurant need to make 20 gallons of a lemonade mixture that is 10% sugar? I think the answer is 8 gallons of 12% lemonade and 12 gallons of 7% lemonade
*December 24, 2014*

**Algebra 1**

thank you
*December 24, 2014*

**Algebra 1**

A local citizen wants to fence a rectangular community garden. The length of the garden should be at least 110 ft and the distance around should be no more than 380 ft. What system of inequalities would represent the possible dimensions of the garden?
*December 24, 2014*

**Good One, Damon**

Oh, yeah. I like it. I think I pooh-poohed that derivation on another problem, thinking you had short-circuited the product rule, but this time I studied it more closely. Of course dv is just a thin circle on top of the cone (pi r^2) times the thickness (dh)!
*December 24, 2014*

**Calculus**

Or, you can use the product rule: v = 1/3 pi r^2 h dv/dt = 1/3 pi (2rh dr/dt + r^2 dh/dt) Then you have to fill in the other quantities to get dh/dt. Note that since r = h/2, dr/dt = 1/2 dh/dt
*December 24, 2014*

**Calculus**

Once you master the math, you can work on the spelling!... we know h = 2r, so r = h/2 v = 1/3 pi r^2 h = 1/12 pi h^3 dv/dt = 1/4 pi h^2 dh/dt So, now just plug in the numbers you have for h and dv/dt to find dh/dt.
*December 24, 2014*

**Math**

which bank is that? I'll put my money there!
*December 24, 2014*

**math**

A:B:C = 3:7:8 A:B+10:C-10 = 3:8:7 That means that b/c = 7/8 (b+10)/(c-10) = 8/7 Solving that, we have b=70 c=80 Now, you can figure a.
*December 24, 2014*

**Algebra 1**

How many solutions does then system of equation have? y-5x = -6 and 3y-15x=-12
*December 23, 2014*

**Algebra 1**

How many solutions does the system of equation have? x-4y =12 and 5x-20y =60
*December 23, 2014*

**Math I Have no idea PlEASE help me**

well, you know that flying east-to-west, the plane goes 270 mi/hr going to the east, it flies at 330 mi/hr. So, just make your table for each 200-mile interval. That's 15 entries in each direction.
*December 23, 2014*

**Algebra 1**

How many solutions does the system of equations have? y=4x +3 and 2y-8x=3
*December 23, 2014*

**Algebra 1**

How many solutions does the system of equations have? x=-4y+4 and 2x+8y=8
*December 23, 2014*

**Geometry**

It might help if you list the vertices of the quadrilateral, say, in clockwise order or something. What you have said gives no real good picture of the figure.
*December 23, 2014*

**math**

Ah, yes. You are correct. I had misread the problem. Good work.
*December 23, 2014*

**math**

Clearly, the fixed charge is always 700. You must want the variable charge per unit. That means you want to solve 700+200x = 5/4(700+100x) unless something else has been garbled.
*December 23, 2014*

**Maths**

6912/(3+4) = 987.4 So, length = 3*987.4 breadth = 4*987.4
*December 23, 2014*

**Algebra**

just write down what you know. If there are x at 5 points and y at 3 points, then x+y = 38 5x+2y = 100
*December 22, 2014*

**Grammer**

since "none" is singular, none of the choices is correct.
*December 22, 2014*

**science **

A running back has 3500 J of kinetic energy and is running at a speed of 8 m/s. Calculate his mass.
*December 21, 2014*

**Integration**

The trapezoidal cross-section for water at depth 1/2 + h/2 = (1+h)/2 So, the surface area of the water at depth h is 10*(1+h)/2 = 5(1+h) So, the volume of the sheet of water is 5(1+h) dh That means that the weight of the water (at 1000kg/m^3) layer is 5(1+h) dh * 1000 * 9.8 ...
*December 21, 2014*

**ap calc**

Is f(x) continuous at x=1? 2x-x^2 = 1 2x^2-4x+3 = 1 So, yes. The derivative exists everywhere in (0,2). So, f(x) satisfies the MVT f(2) = 3 f(0) = 0 So, the slope of the secant is is 3/2 Where does f'(c) = 3/2? 2-2x = 3/2 x = 1/4 y = 3/2 (x-1/4) + 7/16 4x-4 = 3/2 x = 11/8 ...
*December 21, 2014*

**Algebra**

Just plug the numbers into your amortization formula.
*December 21, 2014*

**College Math**

find the mean and the standard deviation. The Z score of 3.1 is how many std it is away from the mean.
*December 21, 2014*

**College Math**

zero The Z score of the mean is always zero, because it is zero std away from the mean. If you really have no clue, it's probably time to review just what a Z score is.
*December 21, 2014*

**College Math**

30(1.6)^n = 30000 1.6^n = 1000 n log 1.6 = log 1000 n = log1000/log1.6 = 14.7
*December 21, 2014*

**Algebra 1**

just plug in the numvers and check. 4 > 4*3-5 ? 4 > 12-5 ? 4 > 7 ? NO So, try the others.
*December 21, 2014*

**Algebra 1**

Which ordered pair is a solution of the inequality? y>= 4x-5 3,4 2,1 3,0 1,1
*December 21, 2014*

**math**

what a deal. I suspect you want to start with what you know: 4s+3j = 181 1s+2j = 94
*December 21, 2014*

**ap calc**

y = x ln x + (1-x) ln(1-x) y' = lnx + 1 - (1-x)/(1-x) - ln(1-x) = lnx - ln(1-x) = ln(x/(1-x)) y'=0 when x/(1-x) = 1 x = 1-x x = 1/2
*December 21, 2014*

**Math-How do I do this problem?**

Hmmm. I get r = 7/24 h so, dr = 7/24 dh r = 35/12 when h=10 v = 1/3 pi r^2 h using the product rule, dv = 1/3 pi (2rh dr + r^2 dh) 12 = pi/3 (2*(35/12)(10)(7/24 dh)+(35/12)^2 dh) 12 = 1225/144 pi dh dh = 1728/1225 pi = 12^3/35^2 pi Maybe you can figure out whether one of us is...
*December 21, 2014*

**Calculus**

The curves intersect at (-4,-12) and (3,-5) So, the area is just the sum of all the tiny rectangles with width dx, and height the distance between the curves: A = ∫[-4,3] (4-x^2)-(x-8) dx = ∫[-4,3] -x^2-x+12 dx = -1/3 x^3 - 1/2 x^2 + 12x [-4,3] = 343/6
*December 21, 2014*

**Calculus**

Try checking here: https://in.answers.yahoo.com/question/index?qid=20101212020426AAEM8Zp and https://answers.yahoo.com/question/index?qid=20131119231723AABFnM7
*December 21, 2014*

**Algebra 1**

What about from the following answers 0,1 -1,0 1,0 0,0 I'm a 68 year old grandfather trying to help his grandson.
*December 20, 2014*

**Algebra 1**

the solution set for y<x is half of the plane. There are infinitely many points on each axis which satisfy the inequality.
*December 20, 2014*

**Algebra 1**

Which point on the axis satisfies the inequality y<x?
*December 20, 2014*

**Algebra 1**

What about from the followuing answers 4 -2 2 -4
*December 20, 2014*

**Algebra 1**

the point on the x-axis is where y=0, SO x - 2y <= 4 now plug in y=0 and you can see what x is. I think you need a bit more information here.
*December 20, 2014*

**Algebra 1**

In the graph of the inequality X - 2y is less then or equal,to 4, which is a value for x on the inequality line and the x axis?
*December 20, 2014*

**Algebra 1**

I'm 68 years old and don't remember some of these things and am trying to help grandson.
*December 20, 2014*

**Algebra 1**

draw the axes. Label each quadrant ++ +- -+ or -- and then let us know, ok?
*December 20, 2014*

**Algebra 1**

If x is greater then or equal and y is greater then or equal to 0 then which quadrant holds the solution?
*December 20, 2014*

**Algebra 1**

the rate of change is the slope of the line. That is, if x changes by 1, how much does y change? In the slope-intercept form, the rate of change (slope) is m, in y = mx+b The point-slope form of a line is y-k = m(x-h) where the line passes through (h,k) with slope m. It's ...
*December 20, 2014*

**physics**

well, you know the equation of motion is h(t) = vt - 4.9t^2 So, h is max at t = v/9.8 So, plug in t=v/9.8 into vt - 4.9t^2 = 1.5 and solve for v.
*December 20, 2014*

**physics please help**

If thrown down with initial velocity v, then just solve 109 - vt - 4.9t^2 = 0 plug in t=2.40 and find v.
*December 20, 2014*

**Physics please help**

the equation of the height is h(t) = 29t - 4.9t^2 Now just find the vertex of the parabola for the max height. Of course, the ball comes down exactly as fast as it went up -- got to conserve that momentum, eh?
*December 20, 2014*

**ap calc**

f(0) = 0 f(√π) = 0 So, we need c in (0,π) such that f'(c) = 0 f'(x) = 2x cos(x^2) 2x cos(x^2) = 0 Clearly c=√(π/2) satisfies the theorem.
*December 19, 2014*

**Math**

just divide each y by its x. Is the ratio constant? If so, that means y/x = k,or y=kx, a direct variation.
*December 19, 2014*

**math**

We have a winner!
*December 19, 2014*

**Math**

Note that y increases 5 when x increases 1. So, the rule will look like y = 5x But, when x=0, 5x=0 and we want y = -3. So, y = 5x-3
*December 19, 2014*

**Intermedia Algebra**

well, you have the formula. Use it. What do you get?
*December 19, 2014*

**Algebra**

Neil: 2 mi/hr current: 1 mi/hr Check: In 1 hour, Neil rowed 1 mi upstream. In 1 more hour, he rowed 3 mi downstream back to camp In those 2 hours, the log floated 2 miles downstream to camp
*December 19, 2014*

**math**

Hmph. Musta missed that. Using 22/7 for pi is just not rational!
*December 19, 2014*

**math**

so, what does 22/7/2 mean?
*December 19, 2014*

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