Tuesday

January 27, 2015

January 27, 2015

Total # Posts: 28,411

**Math**

h(t) = 75 + 80/√2 t - 16t^2 h=0 when t=4.563 The horizontal speed is a constant 80/√2 = 56.57 ft/s So, the ball travels 258.12 ft Hmm. We differ slightly. What did you do? And of course, check my math.
*December 4, 2014*

**GEOMETRY**

the area grows as the square of the radius. So, the radius grows as the square root of the area. Since areaB/areaA = 25, radiusB/radiusA = √25 = 5
*December 4, 2014*

**algebra**

domain: all real numbers except holes and vertical asymptotes vertical asymptotes where the denominator is zero and the numerator is not zero holes where the denominator and numerator are both zero horizontal asymptotes at the x-extremes. When x gets huge, you basically have f...
*December 4, 2014*

**Coll Algebra**

since time = distance/speed, we have d/(5-1) = d/(5+1) + 2 d = 24
*December 4, 2014*

**5th grade math**

Just do regular long division. In the quotient, place the decimal point directly above where it is in the dividend. Then move it to the right the number of decimal places as there are in the divisor. In normal long division with integers, the decimal point is at the right end ...
*December 4, 2014*

**math**

well, there are only a few perfect squares: 16 25 36 49 64 100 121 144 169 196 So, check the next numbers for primality. 17 is prime 26 is not and so on
*December 4, 2014*

**Algebra 1**

the slope is 2, so use the point-slope form to get y+3 = 2(x-1) or y-1 = 2(x-3)
*December 4, 2014*

**Algebra 1**

What is an equation in slope-intercept form for the line that passes through the point (1,-3) and (3,1)
*December 4, 2014*

**chemistry**

find the atomic wt of Ca figure the mol wt of CaCO3 So, the mass of Ca is just wt(Ca)/wt(CaCO3) * 1.229g
*December 4, 2014*

**Chemiry 11**

figure how many moles. Then, each mole contains Avogadro's Number of sulfur atoms.
*December 4, 2014*

**Algebra 1**

y = -2x so, k = -2
*December 4, 2014*

**Algebra 1**

For the equation -4y =8x, what is the constant of variation?
*December 4, 2014*

**math**

the given line has slope 5 So, you want a line with slope -1/5 That line is thus (recall the point-slope form): y-3 = -1/5 (x+10) and you can massage that into whatever form you like.
*December 4, 2014*

**Calculus**

I suspect a typo. Why write "1 sqrt(t)"?
*December 4, 2014*

**Algebra**

the distance s = 1/2 at^2 You have s and a, so just find t.
*December 4, 2014*

**Algebra 1**

thank you
*December 4, 2014*

**Algebra 1**

Suppose y varies directly with x and y = 24 when x =8. What is the value of y when x = 10?
*December 4, 2014*

**algebra**

The vertices involving y>=x are clearly (-2,-2) and (3,3) The rest you can surely find... What did you try? See the solutions at http://www.wolframalpha.com/input/?i=solve+x+%E2%89%A5+%E2%88%922%2C+x+%E2%89%A4+3%2C+y+%E2%89%A4+5%2C+y+%E2%89%A5+x+
*December 4, 2014*

**math**

what, no calculator? .01 is around 1/100, so the answer should be somewhere near 3 or 4
*December 3, 2014*

**Math Help**

The increase is 20 20/50 = 40% (of 50)
*December 3, 2014*

**Math**

Since √5 = 5^(1/2), log √5 = 1/2 log5 Not sure what all the other mumbo jumbo means.
*December 3, 2014*

**Math**

√(2-3x) = 9 2-3x = 81 3x = -79 x = -79/3 Remember: (a-bx)^2 is NOT NOT a^2 - b^2x^2 Not that that matters here, anyway, since √(stuff)^2 is just stuff, whatever stuff you have. (√x)^2 = √(x^2) = x. There is no reason at all to square what's inside ...
*December 3, 2014*

**math**

assuming the x side is parallel to the wall, then 2x+4y = 120 The area is 2xy = 2x(120-2x)/4 = 60x - x^2 The maximum area is thus where x=30 As usual with such problems, the maximum area is achieved when the fencing is divided equally among lengths and widths.
*December 3, 2014*

**Algebra 1**

What is an equation in slope-intercept form for the line that passes through the points (1,-3(), (3,1)?
*December 3, 2014*

**Algebra 1**

Thank you trying to help my grandson with his homework
*December 3, 2014*

**Algebra 1**

What is an equation for the line with slope 2/3 and y intercept 9?
*December 3, 2014*

**Algebra 1**

Suppose y varies directly with x and y = 24 when x =8. What is the value of y when x = 10?
*December 3, 2014*

**Algebra 1**

For the equation -4y =8x, what is the constant of variation?
*December 3, 2014*

**Algebra 1**

What is the slope of the line that runs through points (1,1), (0,3)?
*December 3, 2014*

**Pre-Calc/Trig...**

Since An/An-1 = r (1/An)/(1/An-1) = An-1/An = 1/r so, the ratio between terms is still constant.
*December 3, 2014*

**College Algebra**

If the amounts are x,y,z then we have x+y+z = 14000 .03x + .04y + .05z = 539 z = 3y Now just solve for x
*December 3, 2014*

**Algebra 1**

thank you
*December 3, 2014*

**Algebra 1**

the point 12,9 is included in a direct variation. what is the constant of variation
*December 3, 2014*

**Algebra 1**

Thank you, I'm a grandfather trying to help my grandson.
*December 3, 2014*

**Algebra 1**

suppose y varies directly with x and y = 14 when x = -4 what is the value of y when x = -6
*December 3, 2014*

**Algebra 1**

The ordered pairs 1,4 - 2,16 - 3,64 - 4,256 - 5, 1024 represents a function. What rule represents this function. 1- 4 x power 2- 4x 3- xto the 4th power 4- x+4 my answer is 4x
*December 3, 2014*

**trig**

zero. Why? try drawing the triangle...
*December 3, 2014*

**mathematics**

If you mean 2 2/4, that's 10/4 1/4 / 1/4 = 10 yet, who actually writes 2 2/4 instead of 2 1/2? I suspect a typo. And lose the \\\'s. Try /// for fractions.
*December 3, 2014*

**algebra**

w*4w = 392 That gives you w. Now, you want p = 2(w + 4w)
*December 3, 2014*

**AP CALC. AB**

clearly the tangent is horizontal when x^2-2 = 0 h"(x) = (x^2+2)/x^2 And you know that f(x) is concave up when f"(x) > 0 See that graph at http://www.wolframalpha.com/input/?i=integral+x+-+2%2Fx
*December 2, 2014*

**Calculas**

Draw a diagram. If the man is x feet from the pole, and his shadow has length s, then using similar triangles, we see that s/6.5 = (x+s)/17 2s/13 = (x+s)/17 34s = 13x+13s 21s = 13x s = 13/21 x So, ds/dt = 13/21 dx/dt So, it does not matter how far away he is, his shadow's ...
*December 2, 2014*

**algebra**

3x^4 + 11x^3 = 4x^2 3x^4 + 11x^3 - 4x^2 = 0 x^2(3x^2+11x-4) = 0 x^2(3x-1)(x+4) = 0 ...
*December 2, 2014*

**math**

Between them, A and B cover 22-n miles on the nth day. You can see that this is an A.P. with a = 22 d = -1 So, we want to find Sn such that Sn = 165. So, n/2 (2*22+(n-1)(-1)) = 165 n = 9.2 So, on the 10th day they meet. n =
*December 2, 2014*

**math**

well, that would surely be 15/396
*December 2, 2014*

**Math**

0.8(4) + 0.8(-a) = 5.6a 3.2 - 0.8a = 5.6a 3.2 = 6.4a 0.5 = a
*December 2, 2014*

**Calculas**

You have x^2 + y^2 = 13^2 when x=5, y=12 2x dx/dt + 2y dy/dt = 0 Now plug in your numbers and solve for dy/dt.
*December 2, 2014*

**calculus 2**

well, just do 1 - cosθ = 1 + sinθ sinθ = -cosθ sin π/4 = cos π/4 So, in QII and QIV, sin 3π/4 = -cos 3π/4 sin 7π/4 = -cos 7π/4
*December 2, 2014*

**geometry**

Hint: the other side is 7.
*December 2, 2014*

**algebra**

If tennis is x, then x + x+6.98 = 123.62 Now just find x and figure the other price.
*December 2, 2014*

**Elementary Alegebra**

j = 1.2s j-s = 5 Now just solve for j and s.
*December 2, 2014*

**Earth Science**

Which of the following statements correctly describes the asthenosphere? 1- it is thin cold and rigid layer 2- it is the source of the earth's heat 3- it permits plate motion 4- it occurs only near subduction zones My answer is 1
*December 2, 2014*

**Math**

√(49-25)
*December 2, 2014*

**math**

x^3 - y^3
*December 2, 2014*

**Math help**

Not quite -(-5-p) = 5+p so we have (5+p)^2
*December 2, 2014*

**Business Math**

Looks like it will be 7.35% of $720
*December 2, 2014*

**coordinate algebra**

hint: 3+4 = 7 3*4 = 12
*December 2, 2014*

**math**

why clutter things up with all the words? You clearly know how to write fractions. Benny: 4/10 Brother: 4/10 + 1/10 = 5/10 Sister: (1/2)(4/10) = 2/10 Assuming "him" again refers to Benny. (And it should be "he" anyway) Now add up the amounts.
*December 2, 2014*

**MATH**

Fe = 9/20 Beth = 2(9/20) = 18/20 Tina = 9/20 + 2/20 = 11/20 I think the questions can now be easily answered.
*December 2, 2014*

**physics**

step back, or throw the book really hard away from the table.
*December 2, 2014*

**algebra**

2(w + 3w-1) = 30 solve for w, and then figure the length
*December 2, 2014*

**Algebra**

-3/4 + 1/4 = -1/2 -9/10 + 2/5 = -1/2
*December 2, 2014*

**algebra**

116 - 6*8 = ?
*December 2, 2014*

**language arts**

Mine, too. Normally, the subjunctive is clearly indicated, as in So if you had any sense at all, you would avoid Storm Fever. (But, you clearly do not.) As phrased, it leaves open the possibility that you do have some sense, so based on that condition, you will avoid the movie.
*December 1, 2014*

**algebra**

well, just use what you're told. If the medium side is x, then x-7 + x + x+13 = 57 Now just find x and you're almost done.
*December 1, 2014*

**MATH**

7*5=35 2*4*35 = 280 (new area) 2(7*4+5*2) = 76 (new perimeter) 2(7*2+5*4) = 68 (new perimeter) You don't say which side is 2x and which is 4x larger No idea how to work this without double-digit numbers
*December 1, 2014*

**Math**

(97.65-45)/45 = ?
*December 1, 2014*

**Newtons Law of Cooling**

well, you know that dT/dt = k(68-T) dT/(68-T) = k dt ln(68-T) = kt + c1 68-T = e^(kt+c1) 68-T = ce^(kt) T = 68 - ce^(kt) We know that T(0) = 43, so c=25, and T = 68-45e^(kt) We know that T(12) = 55, so 55 = 68-45e^(12k) 45e^12k = 13 e^12k = (13/45) 12k = ln(13/45) k = ln(13/45...
*December 1, 2014*

**calculus**

You know that the average velocity is [y(3+h)-y(3)]/h So, just plug in the numbers and grind out the answers.
*December 1, 2014*

**Algebra 1**

use the vertical line test to determine if the relation(-6,-2), (-2,6),(0,3),(3,5) is a function
*December 1, 2014*

**Algebra 1**

What is the graph of the function rule? y=I5xI -2
*December 1, 2014*

**Algebra 1**

The ordered pairs(1,4), (2,16), (3,64), (4,256),(5,1024) represent a function. What is a rule that represents,this function? My answer is y=x to the 4th power
*December 1, 2014*

**Algebra 1**

The table shows the relationship between the number of players on a team and the minutes each player gets to play. Players minutes 7 35 8 30 9 25 10 20 Is the relationship a function that ism increasing or decreasing? Is the relationship a function that is linear or nonlinear...
*December 1, 2014*

**Algebra 1**

Write an equation that relates the number of parallelograms in the figure (n), to the perimeter of the figure (P). /_/ /_/_/ /_/_/_/ The top and bottom = 5 each and the sides = 4 each in each figure.
*December 1, 2014*

**Rounding up and down**

#1 0.34 #2 C 0.351 -> 0.4 0.562 -> 0.6 0.445 -> 0,4 #3 0.545 -> 0.55 Most people round up from 5. Some round to the closest even value, which would be 0.54 in this case. Follow the rules you were given.
*December 1, 2014*

**math**

treated in the related questions below.
*December 1, 2014*

**Calculus**

technically, since f(1) is not defined, you need to take the limits as x->1, but you will wind up with the same values.
*December 1, 2014*

**Calculus**

∫[-2,3] f(x) dx = ∫[-2,1] x dx + ∫[1,3] 1/x dx Now you can take it from there. Note that f(1) is not defined.
*December 1, 2014*

**Calculus**

well, which function is not constant?
*December 1, 2014*

**Calculus**

I assume you want the rectangles to have equal widths. Tat would be (5-1)/4 = 1. So, the left sides of the rectangles are at x = 1,2,3,4 the heights are f(1),f(2),f(3),f(4). So, evaluate f there and add up the areas.
*December 1, 2014*

**Math**

2(x+y) = 100 xy = 525 Carry on from there.
*December 1, 2014*

**Trig**

just recall your Pythagorean Theorem. It's also a distance formula.
*December 1, 2014*

**Maths**

This problem is discussed at http://www.beatthegmat.com/how-many-non-negative-integral-solutions-are-possible-t34635.html as you could have discovered with about 5 minutes' work.
*December 1, 2014*

**Pleaaaaaase help with differential graph question**

Sorry, no graphs here. But you know that since f(P) is dP/dt, when f is positive, P is increasing. As for the other items, no idea, since no picture is available. Sounds like P is some kind of exponential or logistic model. Better review those topics.
*December 1, 2014*

**physics**

8.0 rad / (2.56 rad/s) = 8.0/2.56 = 3.125 s Now convert that to minutes...
*December 1, 2014*

**Maths**

well, the first n terms of 2^(n-1) is 2^n - 1 The first n terms of 5n is 5 * n(n+1)/2 So, the sum you want is 2^n - 1 + 5n(n+1)/2
*December 1, 2014*

**Maths**

12 + 12+d + 12+2d = 6(1+r+r^2) But, d=r, so 36+3d = 6(1+d+d^2) 6d^2+3d-30 = 0 2d^2 + d - 10 = 0 (2d+5)(d-2) = 0 So, d=2 or -5/2 The two sequences are thus 12,14,16 6,12,24 with S3=42 or, 12,9.5,7 6,-15,75/2 with S3=28.5
*December 1, 2014*

**Math**

This is just an A.P. with a=4 d=4 The section in question has (64-4)/4 + 1 = 16 terms, so S16 = 16/2 (4+64) = 544
*December 1, 2014*

**College Geometry**

it's just a pyramid. And, of course Euler's formula holds.
*December 1, 2014*

**movie**

Hmmm. Try watching the movie! Failing that, if you are not familiar with America, just be aware that Tiffany & Co. is one of the most famous stores in the country. In particular, they sell fine jewelry and gifts.
*December 1, 2014*

**Precalc/Trig**

Suppose the nearer observer is at a distance x, and the tree has height h. Then, it is clear that h/x = tan30° h/(x+25) = tan20° Now, eliminate x and we see that h/tan30° = h/tan20° - 25 h(cot20°-cot30°) = 25 h = 25/(cot20°-cot30°) h = 24.62 ft
*December 1, 2014*

**Physics**

You can find the appropriate formula here: http://en.wikipedia.org/wiki/List_of_moments_of_inertia
*December 1, 2014*

**math**

The x- and y- changes from the first point to the last are 9 and 15 So, add 1/3 of those values to the first point.
*December 1, 2014*

**Math**

#1: 100000 * 1.1^5 #2: Sum of the first n integers is n(n+1)/2 #3 12 + 2*4/(1 - 1/3)
*December 1, 2014*

**calculus**

Oops. You are correct. So, make the fix and rerun the math.
*November 30, 2014*

**calculus**

The average rate of change between years a and b is (R(b)-R(a))/(b-a) Here, both intervals are 50 years, so things are convenient. You want to show that R(150)-R(100) ≈ 2(R(100)-R(50)) So, just plug in your numbers and see what you get.
*November 30, 2014*

**Differential equations in Calculus...plsssss help?**

so. you have dT/dt = -T/15 + 5 = -1/15 (T-75) dT/(T-75) = -1/15 dt ln(T-75) = -t/15 + k T-75 = e^(-t/15 + k) T-75 = ce^(-t/15) T = 75 + ce^(-t/15) Now, you are told that T(0) = 105, so 105 = 75 + ce^0 c = 30 T(t) = 75 + 30e^(-t/15) as desired in part (g) So, the coffee starts ...
*November 30, 2014*

**Differential equations in Calculus...plsssss help?**

Hard to see just what you wrote, but I'm guessing dT/dt = -1/(15T+5) (15T+5) dT = -dt No, that can't be right, if you want an exponential function. How about dT/dt = 15T+5 then we have dT/(3T+1) = 5dt ln(3T+1) = 5t+k 3T+1 = ce^5t T = (ce^5t - 1)/3 Hmm. Not that either...
*November 30, 2014*

**Math**

#1 You have an A.P. with a = 100 d = 50 S31 = 31/2(2*100 + 30*50) #2 You have a G.P. with a = 16 r = 1/4 So, find T7 and 2S6-16+T7 the strange sum is because you have just a drop on T1 and a bounce on T7, and not 7 complete round trips
*November 30, 2014*

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