Wednesday

February 10, 2016
Total # Posts: 37,530

**math**

3/2 (2a+2d) = 39 (a+d+5)/(a+1) = (a+2d+12)/(a+d+5) a=11, d=2 AP: 11,13,15 GP: 12,18,27 a=26, d= -13 AP: 26, 13, 0 GP: 27,18,12
*January 25, 2016*

**Maths**

There is no way to add 3 odd numbers and get an even result. I suspect there is more to this question than is shown here.
*January 25, 2016*

**math-story prob**

If the fee is f and the cost of a basket is c, then f+40c = 715 f+400c = 5935 Multiply the 1st equation by 10 so we can eliminate c: 10f + 400c = 7150 f + 400c = 5935 subtract and you have 9f = 1215 f = 135
*January 25, 2016*

**calculus 2**

see http://www.jiskha.com/display.cgi?id=1453510325 and change the numbers
*January 25, 2016*

**calculus 2**

See http://www.wolframalpha.com/input/?i=plot+y%3Dcos%28pi*x%29%2C+y%3D12x^2-3 the curves intersect at (-1/2,0) and (1/2,0). So, it's just a straightforward integral. Since things are symmetric, the area is just 2∫[0,1/2] cos(πx)-(12x^2-3) dx
*January 25, 2016*

**maths**

T4 = 11 T8 = 2*11+5 = 27 so, T8-T4 = 4d = 16 d = 4 a+3d = 11, so a = -1 S20 = 20/2 (2a+19d) = ...
*January 25, 2016*

**Math**

not usually, even for linear functions: f = ax+b g = cx+d f◦g = ag+b = a(cx+d)+b = acx + ad+b g◦f = cf+d = c(ax+b)+d = acx + bc+d with suitable values for a,b,c,d it might work. For other functions, all bets are off f = e^x g = x^2 f◦g = e^g = e^(x^2) g◦...
*January 24, 2016*

**College Algebra**

.12x + .09(30000-x)
*January 24, 2016*

**math**

what a load of rubbish. If the leaning part has length h, touches the ground x feet from the base, and the standing part has length y, then y/h = sinθ y/x = tanθ Then the pole is y+h feet tall. You can play cutesy games with [c] and [e], but when you finally get ...
*January 24, 2016*

**Algebra**

well, it doubles 8 times in 24 hours. So, it has grown by a factor of 2^8 10 * 2^8 = ?
*January 24, 2016*

**QUADRILATERAL**

Something is missing. I can draw A,B,C ok, but then D can be any point on a circle centered at C with radius 16. Is it a trapezoid? AB parallel to CD or angle A a right angle? Lots of ways to go here.
*January 24, 2016*

**Math**

Looks like a 3-4-5 right triangle to me.
*January 24, 2016*

**Grde 12 math**

If A,B,C,D are the angles of a quadrilateral, then they add to 360. So, (5y+10)+(5y+10)+C+110 = 360 10y+130+C = 360 10y+C = 230 Without some other information, I cannot uniquely identify y or C
*January 24, 2016*

**Calc II**

4x^4+11x^3 = x^3 (4x+11) so, the log is 3lnx + ln(4x+11) ln(1/5 x^3) = ln(1/5)+3lnx = 3lnx - ln5 z = 6lnx + ln(4x+11) - ln5
*January 24, 2016*

**Math**

-1.99, -1.80, -1.23, -1, -0.87, -0.43, -0.1250001 to name just a few...
*January 24, 2016*

**Algebra 1**

There are various classes of numbers. In order of increasing "size" we have whole numbers: 1,2,3,4,... integers: ...-3,-2,-1,0,1,2,3,... rational numbers (fractions): 1/2, 3/7, 98/113, etc Rational numbers include also terminating decimals: 2.5, 123.456, 99.32764, ...
*January 24, 2016*

**chemistry**

You know that PV/T is constant. So, you want T' such that PV/T = (4P)(4V)/T' T' = (16PVT/PV) = 16T Now just plug in your value of T.
*January 24, 2016*

**MTH**

That's "theorem" with an uncorrected typo. Type in (x+y)^25 at wolframalpha.com to see the whole grisly expansion. If I were a teacher, I'd accept 25 Σ 25Ck x^(25-k) y^k k=0 since it would indicate that you know about binomial coefficients and their use ...
*January 24, 2016*

**Maths**

the midpoint of the diameter is the center of the circle: (6,4) The radius is half the diameter: 1 (x-6)^2 + (y-4)^2 = 1
*January 24, 2016*

**Mathematics**

π^3 = 31.0
*January 24, 2016*

**Maths**

maybe all he wanted was confirmation of all his hard work.
*January 24, 2016*

**Math @Afeez**

Ahem. 40/(2.5^n-1) = 40*2.5/2.5^n = 100/2.5^n = 100 / (10/4)^n = 100 * (4/10)^n
*January 24, 2016*

**Math**

recall that 4^1=4 4^2=16 4^3=64 But, each term is multiplied by 10,1,.1,... = 10^(2-n) so, Tn = 4^n * 10^(2-n) = 100 (4/10)^n
*January 24, 2016*

**Maths**

velocity = 2t-t^2 acceleration is dv/dt = 2-2t distance is s = ∫v dt = t^2 - 1/3 t^3 + C Since s(0) = 0, C=0 Now you can answer the questions
*January 24, 2016*

**math/trigo**

If the angle is x, then tan x = 22/62 Review your basic trig functions. It will almost always help if you draw a diagram of the situation.
*January 24, 2016*

**Calculus**

Review your chain rule: if y = a^u where u is a function of x, then y' = ln(a) a^u u' So, for this one, f'(x) = ln(a) a^(-bx) (-b)
*January 24, 2016*

**Algebra Applications**

If Jackie's speed is x, their combined speed is x + x+9 = 2x+9 The cover the 115 miles in 5 hours, so since distance = speed*time, (2x+9)(5) = 115
*January 24, 2016*

**Math**

just the reverse. If I ask you how much more 10 is than 3, do you do 3-10?
*January 24, 2016*

**algebra**

so, what's te problem? You have the rule, so just start pluggin in values for n: 1,2,3... (a) 4(1)-1,4(2)-1,4(3)-1,... = 3,7,11,... (b) 1^3,2^3,3^3,... = 1,8,27,... and so on for the others
*January 24, 2016*

**Algebra**

Normal and <small>small</small> text
*January 23, 2016*

**Calc 1**

sin(10π/2) = sin(5π) = 0 the slope of the line joining (1,0) and (2,0) is 0 something is wrong with this picture.
*January 23, 2016*

**Calc 1**

you want the points (2, sin10π/2),(1.5, sin10π/1.5) and so on Do not expect the slope of the secant to approach a limit. It will oscillate between values approaching -1 and 1
*January 23, 2016*

**Math**

sort of. 3/4 = .75 .75/100 = .0075 so, 3/4% of 75 is .0075 * 75
*January 23, 2016*

**Math**

no, because 8/32 is 1/4 How about 9/32, since 1/4=8/32 and 5/16=10/32
*January 23, 2016*

**maths**

what about it?
*January 23, 2016*

**maths**

well, 8100 = 100*81 = 10^2*9^2 = 10^2*3^4 As you can see, there are now two ways to work with the 10^2, so you'll have to pick one.
*January 23, 2016*

**Math**

C'mon, guys - the midpoint has coordinates that are the average of the endpoints. (B) is the obvious answer. 1.5 is midway from -3 to 6 It is 4.5 away from each end.
*January 23, 2016*

**calc 1**

it says to start at t=2, not t=0. So, you want the average velocity from 2 to 2.5 y(2) = 28 y(2.5) = 15 so, the average velocity is (15-28)/(2.5-2) = -13/.5 = -26 See http://www.wolframalpha.com/input/?i=%28%2846t-16t^2%29-%2846*2-16*2^2%29%29%2F%28t-2%29+for+t%3D2.01%2C2.05%...
*January 23, 2016*

**math**

without trying complicated algebraic solutions, you know that 17 = 8+9 = 2^3 + 3^2 Now just check to make sure that also works in the other equation. It does not: 2^3 + 2 + 3^2 + 1 is not 5. If you mean 2^(x+2) + 3^(y+1) = 5 then since 2^1 + 3^1 = 5, x = -1 and y = 0 I can'...
*January 23, 2016*

**math**

done below. your eventual solution is correct.
*January 22, 2016*

**Homework for Math**

check your text. The way to factor the difference of two cubes is (a^3 - b^3) = (a-b)(a^2+ab+b^2) Here, you have a=x b=2 Simple as that.
*January 22, 2016*

**Physics**

no idea. What did you discuss?
*January 22, 2016*

**math**

AH FINALLY. If they need 1 4/5 on Wed, then no, 3/4 is not enough.
*January 22, 2016*

**science (chemistry)**

first check with google. Just type in your question. The very first reference discusses the topic. For questions of a general nature, online help via google will almost always be faster and more complete than waiting for a tutor.
*January 22, 2016*

**Math**

as always, length * width = (3/4)(1/3) = 1/4
*January 22, 2016*

**Math**

basically the same incomplete setup as your previous post.
*January 22, 2016*

**pls help me math**

Not unless you meant to type (3*6)^(2x)
*January 22, 2016*

**pls help me math**

6^(2x) = (6^2)^x = 36^x Now it should be clear
*January 22, 2016*

**math**

no idea. How much does it take (x qts) to do the whole job? Whatever that is, do you have 1 2/3 + 1 3/4 + 3/4 >= x ??
*January 22, 2016*

**geometry**

think of the main diagonal as the hypotenuse of a right triangle, where the base is the diagonal along the base of the cube, and the height is the height of the cube. Now you can see that the main diagonal has length d = √(4^2+4^2+4^2) = √48
*January 22, 2016*

**calculus 2**

for some nice graphing, with scalable axes, go to https://rechneronline.de/function-graphs/ Type in your functions (up to 3 of them). (Type them in, if you copy and paste from the post, the minus sign is really a dash, which the web site does not interpret.) Set the x range ...
*January 22, 2016*

**calculus 2**

Pretty straightforward integral. Where do you get stuck? You can always check your answer at wolframalpha.com if you are unsure.
*January 22, 2016*

**calculus 2**

Well, you know the tangent line at (1,3) is y-3 = 6(x-1) y = 6x-3 x = (y+3)/6 See the graph at http://www.wolframalpha.com/input/?i=plot+y%3D3x^2%2C+y%3D6x-3 Now, if you integrate along x, you have to split the region at x=1/2, where the lower boundary changes from the x-axis ...
*January 22, 2016*

**pls help me**

The >= condition indicates you will need a solid line, because 3x+y = 10 is part of the solution. So, B and D are the only possibilities. Now draw that line. Since you want 3x+y >= 10 you shade the part of the plane above the line, as that's where the sum of 3x+y is ...
*January 22, 2016*

**Algebra**

in some cases, yes. If you want to factor it, which two factors of 6 add up to 5?
*January 22, 2016*

**MATH PLS HELP ME**

None of those choices. I suspect a typo. If you want to check, just type into the google box 3^(2/3) or any of the choices. You will see that there's no joy. However, 3^(3^2) = 3^9 2^(3^2) = 2^9 3^(3^3) = 9^(3/2) = 27
*January 22, 2016*

**Calculus**

well you know that if you think of the solid as a stack of washers of thickness dy, v = ∫[0,8] π(R^2-r^2) dy where R=x=√(100-y^2) and r =6. So, v = ∫[0,8] π(100-y^2-36) dy Looks like your 2nd choice above.
*January 22, 2016*

**Ms sue or damon pls help me with mathhhhhhhhhhhhh**

stop whining. You know that a box with dimensions x,y,z has volume xyz. So, just multiply things out. box volume (all dimensions in feet) is v = (7)(3/4)(1/2) = 21/8 = 2.625 ft^3 Now can you figure how many bags that will take?
*January 22, 2016*

**Calculus**

as you say, you have to think of the solid as a stack of washers, of thickness dy. So, v = ∫[1,16] π(R^2-r^2) dy where R = 4 and r = x = √y. So, v = ∫[1,16] π(16-y) dy = 225π/2 As a check on your answer, think of the solid as a set of nested ...
*January 22, 2016*

**Math**

Not even close. The solid has six surfaces -- three pairs of parallel rectangles. So, the area is 2(7*9 + 7*11 + 9*11) = 478
*January 22, 2016*

**maths**

clearly the common difference is 5, from the first two terms. so, m-(k+1) = 5 now, the common ratio tells us that m/(k+1) = 5k/m solving both those equations, we get (k,m) = (4,10) and the terms are 0,5,10,20 and you can see the AP and GP
*January 22, 2016*

**MATH**

1 hectare = 10^8 cm^2 so, the thickness is 0.5cm^3 / 10^8 cm^2 = ? cm
*January 22, 2016*

**math**

1/5 * 1/3 = 1/15
*January 22, 2016*

**algebra**

If x was invested at 3%, then the rest (25000-x) was invested at 5%. So, just add up the interest: .03x + .05(25000-x) = 1100
*January 22, 2016*

**Math**

it will be any number with a 3 in the hundred's place. Your answer is just one of them.
*January 22, 2016*

**algebra**

x+(66-x) = 3x+6
*January 22, 2016*

**maths**

if the roots are a,2a,b then a+2a+b = 7 2a^2b = -36 a*2a + ab + 2ab = 0 or, a(2a+3b) = 0 so, b = -2a/3 Solve those and you find 3,6,-2
*January 22, 2016*

**pre calculus**

The tires will turn (218*5280*12)/(25π) times There are 360 degrees per revolution ...
*January 21, 2016*

**pre calculus**

Draw a diagram. assuming the line runs along the bottom of the pool, The angle is x, where tan(x) = 9/√(25^2+30^2)
*January 21, 2016*

**Algebra**

b(x) = f + rx
*January 21, 2016*

**solid mensuration**

since the base is not square, the base angles on unequal sides cannot be the same. So, which side(s) are we talking about? Anyway, once you have decided on the side to pick, the height is s tan30 = s/√3 where s is the length of the base side adjacent to the sloping face.
*January 21, 2016*

**Math**

2/6 * 30
*January 21, 2016*

**math**

(100)(90)(80) - (100-4)(90-4)(80-4)
*January 21, 2016*

**English**

#4 is a prepositional phrase. Even though "to" is used for infinitives, "the library" is not a verb. #6 "source" is a noun #7 "us" cannot be any kind of nominative; it is in the objective case. So, what kind of object is it? #10 better ...
*January 21, 2016*

**mathu**

28 * w = 280
*January 21, 2016*

**comparing decimals**

well, it has to be a number between 2.80 and 3.40 There's only one of those among the choices.
*January 21, 2016*

**Math**

1000oz/2hr * 1c/16oz * 1hr/60min = (1000)/(2*16*60) c/min
*January 21, 2016*

**math help**

Nope. 3.66 is the largest of the values, but when using negative numbers, larger values are less than smaller ones. Plot them on the number line. The farther to the left you go, the less the number.
*January 21, 2016*

**history help**

google is your friend. Much discussion provided.
*January 21, 2016*

**Science**

I think you'd better reconsider your answer. Immunity is internal to the body. Which of the choices is external?
*January 21, 2016*

**physics 1**

(1/3)(13ac*43560ft^2/ac)(480ft)(.3048m/ft)^3 = 2.5656*10^6 m^3
*January 21, 2016*

**physics 1**

volume in ft^3: (80ft)(22ft)(8ft) Since 1ft = .3048m, volume in m^3 = (80ft*.3048m/ft)... = (80)(22)(8) (.3048)^3 m^3 now do the same with (100cm/m)^3
*January 21, 2016*

**science**

find some insulating matter.
*January 21, 2016*

**math i need help**

I dunno -- it sure looks like Alg1 to me...
*January 21, 2016*

**English**

Seems to me that church bells would become bells of the church. I've only run across long form possessives in Spanish, and the rules are somewhat different there.
*January 21, 2016*

**Calculus**

well, you want |tan(x)| = 1 tanx = 1 or -1 you know that tan π/4 = 1 so use that as your reference angle. The rest is easy. . . . right?
*January 21, 2016*

**Algebra**

all you have to do is rearrange terms so that the equation is in the form Ax + By = C Can you not figure out how to get the x stuff on the left side?
*January 21, 2016*

**Algebra**

1st step: clear the fraction by multiplying by 5: 5y = -2x-3 Now you finish it up.
*January 21, 2016*

**math**

the first two walls are 2 tiles wide The third wall is 1 tile wide. Total length is 5+9+2 = 16 ft = 8 tiles long So, if you can use the cut pieces of tile, that's 8x5 = 40 tiles Those are some big tiles!
*January 21, 2016*

**History**

or, just click on your name above, and you will get a list of all your questions.
*January 21, 2016*

**Math**

good job.
*January 21, 2016*

**Math**

1-4 ok #5 you have chosen 48% of 30, not the correct value. Do it like #1.
*January 21, 2016*

**Math**

or, picking up at (7a^2 - 7)/(a-1) = 84 7(a-1)(a+1) / (a-1) = 84 7(a+1) = 84 a+1 = 12 a = 11
*January 21, 2016*

**MATHS**

1/t = 1/3 - 1/5 now solve for t.
*January 21, 2016*

**math**

regardless of the total mass, the proportion is clearly 16:2
*January 21, 2016*

**math**

area = 2(24*27+24*10+27*10) the area does not double: original area: 2(xy+xz+yz) new area: 2(2x*2y+2xz+2yz)
*January 21, 2016*

**math**

all: 2*2.5^2 + 4*2.5*3.5 to exclude the bottom, subtract 2.5^2 from that total. now compare in whatever way you want.
*January 21, 2016*

**math**

if the squares have sides x and y, then 4x+4y = 100 or, x+y=25 x^2+y^2 = 425 My vast experience tells me instantly that 425 = 400 + 25 = 20^2+5^2
*January 21, 2016*

**Math**

since time = distance/speed, if the bus's speed is x, then 40/x + 40/(x+20) = 9/10 Now just find x, and x+20
*January 20, 2016*

**Calculus**

9cos2x - 27cosx + 18 = 0 9(2cos^2x-1)-27cosx+18 = 0 18cos^2x - 27cosx + 9 = 0 2cos^2x - 3cosx + 1 = 0 (2cosx-1)(cosx-1) = 0 cosx = 1/2 or 1 Take it from there.
*January 20, 2016*