Sunday

July 5, 2015

July 5, 2015

Total # Posts: 32,100

**math**

If you mean ∫ 1/(t^2-1)^2 dt try using partial fractions: 1/(t^2-1)^2 = 1/4 (1/(t+1) + 1/(t+1)^2 - 1/(t-1) + 1/(t-1)^2) each of those is easy to integrate.
*May 26, 2015*

**Math**

a+5d = 5a a+10d = 2(a+4d)+3 Now you can find a and d, and then a+7d.
*May 26, 2015*

**math**

Draw a Venn diagram. You will see that 28 like some sport. So, 2 like none of them.
*May 26, 2015*

**DIFFERENTIATION**

if the base has side x and the tin has height y, then x^2 y = 864 y = 864/x^2 The surface area a is a = x^2 + 4xy = x^2 + 4x(864/x^2) = x^2 + 3456/x da/dx = 2x - 3456/x^2 = (2x^3-3456)/x^2 da/dx=0 when x=12. Now find the area.
*May 26, 2015*

**precal**

just start with -4pi/3 and start adding 2pi. You will run into two of the other three values. The remaining one is a different angle.
*May 26, 2015*

**precal**

4sin^2 = 4cos + 1 4 - 4cos^2 = 4cos + 1 4cos^2 + 4cos - 3 = 0 (2cos-1)(2cos+3) = 0 so, cosx = 1/2 or -3/2 -3/2 is not a choice, so just find where cosx = 1/2.
*May 26, 2015*

**Precalculus**

Review your trig function definitions. For this triangle, tanθ = 7/5
*May 26, 2015*

**Precalculus**

it's exactly 60/√(60^2+85^2)
*May 25, 2015*

**algebra**

nope. is 2(3+4) = 2*4? Review the distributive property: (-2)(x-3) = (-2)(x)+(-2)(-3) = -2x+6 You cannot combine x-3 into -3x
*May 25, 2015*

**Algebra**

that would be correct.
*May 25, 2015*

**Algebra**

well, what is the smallest number which is a multiple of 2,4,8 and 12?
*May 25, 2015*

**Algebra**

2 is the only number which divides both terms.
*May 25, 2015*

**Algebra**

well, 7*3 = 21, so think again
*May 25, 2015*

**Math**

so, where did the 3 come from? One side of ABC is 20. So, if a scale factor of 0.5 is applied, the corresponding side of CDE is 0.5*20 = 10 Now do the same for the other two sides.
*May 25, 2015*

**Math**

How can that be your answer? It asks for the lengths of all the sides of CDE. What the heck is 1.5 supposed to be?
*May 25, 2015*

**Math**

when you say "related" it's not quite clear which way the scale factor is applied. if ABC is .5 CDE, the all the sides of ABC are 0.5 as big as those of CDE. if CDE is 0.5 ABC, then all the sides of CDE are .5 as big as those of ABC. So, pick the right one, and ...
*May 25, 2015*

**Algebra**

find the highest power of primes and variables that divide both terms: 14abc = 14abc 28a^2b^2c^3 = 14abc * 2abc^2 So, the GCF is 14abc It divides both terms, but no higher powers of anything will do so.
*May 25, 2015*

**Math**

5^2 = 5x5 5^9 = 5x5x5x5x5x5x5x5x5 5^11 = 5x5x5x5x5x5x5x5x5x5x5 = (5x5)x(5x5x5x5x5x5x5x5x5) So, when you multiply powers, you just add the exponents.
*May 25, 2015*

**Math**

so are you saying it could be stratified?
*May 25, 2015*

**Math**

Identify the sampling,method. You want to determine the number of text messages students at your school send in a month. You go to the cafeteria and ask every 4th student that walks in. a- random b- systemic c- stratified d-m none of these My answer is none of the these ...
*May 25, 2015*

**Algebra 1**

What are the solutions to the system? y=x^2+5x-9 y+2x+1
*May 25, 2015*

**Algebra 1**

Since opening night, attendance at Play A has increased steadily, while Play B first rose then fell. Equations modeling the daily attendance y at each play are shown below, where x is the number of days since opening night. On what day(s) was the attendance the same at both ...
*May 25, 2015*

**Math**

my answer is 208.02 meters
*May 25, 2015*

**Math**

A model rocket is launched from a roof into a large field. The path the rocket can be modeled by the equation y=-0.04x^2+8.3x+4.3 where x is the horizontal distance in meters, from the starting point on the roof and y is the height in meters, of the rocket above the ground. ...
*May 25, 2015*

**Math**

Sorry I think that it is 439.20 meters in 9.2 seconds
*May 25, 2015*

**Math**

A catapult launches a boulder with an upward velocity of 92 m/s. The height of the boulder, h, in meters after 1 seconds is given in the function h= -5t^2+92t+16. How many seconds does it take to reach maximum height? What is the boulders maximum height?
*May 25, 2015*

**math**

I don't see any way. The number of yellow birds must be a multiple of 20 less than 100. So, if there are 20 yellow, b+g=80 7b+5g=99 If 40 yellow, b+g=60 7b+5g=98 If 60 yellow, b+g=40 7b+5g=97 If 80 yellow, b+g=20 7b+5g=96 None of those setups has positive integer solutions...
*May 25, 2015*

**math**

recall the formula for the circumference of a circle of radius r: c = 2πr Now just plug in your numbers.
*May 25, 2015*

**Math**

4k+1 = 5n+2 4k = 5n+1 So, what multiple of 4 is 1 more than a multiple of 5? k=4, n=3 So, 17 students.
*May 25, 2015*

**Algebra**

If each tray originally had n muffins n + 5 >= 20 n >= 15 so, there were originally 6n >= 90 muffins
*May 25, 2015*

**Algebra**

if the prices are n and s, then we have 14n + 4s = 250 7n + 4s = 170 now just find c and s. Just looking at the numbers, I suspect a typo, but go with what you have written.
*May 25, 2015*

**algebra (check my work)**

yes, as could could check: .60 * 40 = 24
*May 25, 2015*

**math**

s = rθ where θ is in radians. So, since π radians is 180°, s = 9 * 69 * π/180
*May 24, 2015*

**Coordinate Graphing**

3x+2 = 5 x = 1 so, plot (1,5)
*May 24, 2015*

**combinatorics**

first, how many edges are there on an icosohedron? Then, since there are duplicates, you will have 30Pn/(10!10!10!) ways to arrange the toothpicks. But, there are rotational symmetries which make multiple solutions really the same thing.
*May 24, 2015*

**Math**

v = x(20-2x)^2
*May 24, 2015*

**math**

the base is a square of side 6. So, each face is a triangle of base 6 and altitude 5.
*May 24, 2015*

**math**

Hmmm. ACtually, on the stretch, I'd gave to say neither. a^x passes through (0,1) for any value of a. So there can be no vertical scale factor. The stretch/compression is reversed as you cross the y-axis.
*May 24, 2015*

**math**

if x>0, 3^x > 1 if x<0, 3^x is between 0 and 1. There is no value of x that will produce a negative result. As for the stretch, I have to ask again, compared to what? 3^x is stretched when compared to 2^x, but it is compressed when compared to 4^x.
*May 24, 2015*

**math**

I answered this on Friday. See the related questions below. Was there something unclear?
*May 24, 2015*

**math**

42
*May 24, 2015*

**Combinatorics**

well, using 24 1x1 tiles is one way. Using 2x2 tiles, only one tile will fit across. It can be on the left or right side. So, a single 2x2 tile can be placed in 2x7=14 places. Now consider using more than one 2x2 tile. Figure how many places it can slide around into. I'm ...
*May 24, 2015*

**trigonometry**

as always, draw a diagram. If the building's height is h, then you can see that (h-2)/35 = tan 60° If you draw an equilateral triangle, and drop an altitude to one side, you have a 30-60-90 triangle, whose sides are in the ratio 1:√3:2. You know that the ...
*May 24, 2015*

**Math**

that would be 1.7km/5s = 0.34 km/s
*May 24, 2015*

**Math**

60P5 = 60!/55!
*May 23, 2015*

**Math**

if you had 60 songs how many different ways can you load 5 songs
*May 23, 2015*

**math**

see the related questions below
*May 23, 2015*

**math**

I agree
*May 23, 2015*

**Grammar**

or just "to be"
*May 23, 2015*

**Integers**

8 * -17
*May 23, 2015*

**Math**

is A adjacent to or opposite θ?
*May 23, 2015*

**algebra**

inverse variation means that xy = k, a constant. so, the first is xy=10 and the second is xy = ?
*May 23, 2015*

**algebra--1 question**

well, consider that 4b^3+5b-3 = (2b-1)(2b^2+b+3)
*May 23, 2015*

**math**

How about some actual math notation? is it x=1+√2+√3 and x^4-4x^3-4x^2+16x-8 = 0? I don't see any useful tricks here. Just start expanding the powers. x^4 = 80 + 48√2 + 40√3 + 32√6 Expand the others and then things will cancel out.
*May 23, 2015*

**Mathematics**

this is a stupid question. mean, mode, median relate to collections of data. You have no such set of measurements. Also, your question is bogus. How can you drive 80 km/h at a speed of 63 km/h?
*May 23, 2015*

**Geometry**

Are V and T inside or outside triangle PRS?
*May 23, 2015*

**Algebra**

(x-9)5 = x(5)-9(5) = 5x-45 just as (12-7)(5) = 5(5) = 25 12*5 - 7*5 = 60-35 = 25
*May 23, 2015*

**Algebra**

should have stayed with 36 1+3+5+7+9+11 = 36 In fact, if you add up the first n odd numbers, the sum is n^2. How did you decide on 11? 1+3+5=9 and you still had three rows to go.
*May 22, 2015*

**physics**

well 1A = 1C/s. You have 5uC/2s = 2.5 uC/s = 2.5uA
*May 22, 2015*

**Math**

surely there are online resources you can investigate. And, believe it or not, most teachers are not ogres.
*May 22, 2015*

**Math**

surely there's a way for you to check on that for yourself...
*May 22, 2015*

**Science**

usually 14 lb/in^2
*May 22, 2015*

**Math**

area of triangle base: 1/2 bh volume of prism: base.area * height so, what do you get?
*May 22, 2015*

**Math**

in posers of 7, you have 7^(-2n) + 3 = 7^(1/2) Now, in general, that's tough. I suspect you meant (1/49)^(n+3) = √7 Then we have 7^(-2(n+3)) = 7^(1/2) -2(n+3) = 1/2 n+3 = -1/4 n = -13/4
*May 22, 2015*

**math**

y=a^x opens up for any value of a>0 domain is all reals range is all y > 0 no vertex a^0 = 1 for all a>0 stretch factor: compared to what?
*May 22, 2015*

**Combinatorics**

There are 500 even integers. 105 = 3*5*7 So, throw out all the multiples of 3,5,7
*May 22, 2015*

**math**

6000/(1+.03/2)^(2*8) = 4728.19
*May 22, 2015*

**Math**

that is just the number of permutations of 5 things out of 6: 6P5 = 6!/1!
*May 22, 2015*

**geometry**

The center is the midpoint of PQ: (-3,4) The radius is half the length of PQ: 1/2 √(14^2+4^2) Now, knowing the center and the radius, you know that the equation is (x+3)^2 + (y-4)^2 = r^2
*May 22, 2015*

**Math**

cone: area = πrs volume = 1/3 πr^2h = π/3 r^2√(s^2-r^2) hemisphere: area = 2πr^2 volume = 2/3 πr^3 So, plug in your numbers and you will get the desired answers. If not, come back with your work and we can see where you went wrong.
*May 22, 2015*

**physics**

kaBOOM!
*May 22, 2015*

**maths**

tan7θ tan3θ = 1 express in terms of sin and cos: sin7θ sin3θ = cos3θ cos7θ cos3θ cos7θ - sin7θ sin3θ = 0 Things should be starting to look familiar now . . .
*May 22, 2015*

**math**

experimental loaded dice!
*May 22, 2015*

**math**

the vertex of ax^2+bx+c is at x = -b/2a In this case, that is 750/50 = 15, not 9. v(15) = 4375
*May 22, 2015*

**math**

well, that would just be the difference between the two temperatures. How do you find the difference between two numbers? For example, how much bigger is 100 that 20?
*May 21, 2015*

**Physics**

I see a lot of verbage, but nothing related to actually solving this problem. Draw a diagram of the vectors involved. Clearly, sin α = 10/80, so α = 7.18° The speed at touchdown will be 80 cosα = 79.37 mi/hr
*May 21, 2015*

**Physics**

nope: C 1/20 = 1/8 + 1/x x = -13.3
*May 21, 2015*

**Math**

stupid cursing filters! 8/2 = 4 cages of c**katiels 32/10=3.2, so 4 cages of parakeets 28/10=2.8, so 3 cages of finches
*May 21, 2015*

**Math**

ooops. negative multiplication changes direction: -2x < 9 x > 9/-2 x > -4.5
*May 21, 2015*

**math**

see related questions below
*May 21, 2015*

**algebra**

original amount: x apples Becky gets (x+1)/2, leaving Joy (x-1)/2 Gayle gets (x+1)/4, leaving Joy (x-3)/4 Bonnie gets (x+1)/8, leaving 1 left over x - (x+1)/2 - (x+1)/4 - (x+1)/8 = 1 x = 15 or, working backwards, there were ((1*2+1)*2+1)*2+1 = 15 apples to start
*May 21, 2015*

**MATH PRACTICE**

if you look at the coordinates, you just have a right triangle, with legs of length 4 and 7. So, figure the hypotenuse and add 'em up. I get something close to 19.
*May 21, 2015*

**Algebra**

√(1/5) - √5 1/√5 - √5 (1 - √5√5)/√5 (1 - 5)/√5 -4/√5
*May 21, 2015*

**Zoneton**

formatting. Should have been -2x < 9 x > ??? Swap sides to get -9 < 2x -9/2 < x or, x > -9/2
*May 21, 2015*

**Math.**

Clearly you need to review your shapes and their volumes. v = pi/3 r^2 h r=12 and h=10, so v = 3.14/3 * 12^2 * 10 = 1507.2 in^3
*May 21, 2015*

**English**

not necessarily. #2 is just motion #1 also implies intent -- to eat you.
*May 21, 2015*

**Maths**

well, which of them tends to oscillate between a max and a min on a regular (say, daily) basis?
*May 21, 2015*

**math**

mean
*May 21, 2015*

**Calculus and quadratic equations**

The data points are: (0,10000), (3,7075), (6,6400), (9,5275) The instructions say: If the last digit of your Student ID No. is an integer power of 2, then you are to use the initial investment value and data from 3 weeks and 6 weeks to work out the model. So, now you know ...
*May 20, 2015*

**math**

looks like 6 to me there are 3 ways to make the first move. Then from the new corner, there are 2 ways to continue. Then there is a single last move.
*May 20, 2015*

**physics**

the horizontal speed is 17.32 m/s So, the package falls for 750/17.32 = 43.30 seconds So, you need h where h + 10.0t - 4.9t^2 = 0 and t = 43.3 Now you can carry on with the other parts,
*May 20, 2015*

**English**

The expression is "have it easy." similarly expressions: Some like it hot. I can't get it right. Using "easily" would indicate the having, rather than what is being had. (Also, I've never heard anyone say it!)
*May 20, 2015*

**Geometry**

I'd say the distance formula, given the definition of a parabola.
*May 20, 2015*

**Trig - My Bad**

I messed up on my sign (QII) So, Reiny, how did you get 5/12? That was -tanØ
*May 20, 2015*

**Trig**

Not sure I like your values: sin2θ = 2sinθcosθ = 2(-5/13)(-12/13) = 120/169 cos2θ = 2cos^2θ-1 = 2(144/169)-1 = 119/169 tan2θ = sin2θ/cos2θ = 120/119
*May 20, 2015*

**Trig**

since π < θ < 3π/2 (QIII), sinθ = -5/13 tanθ = 5/12 Now just plug those into your double-angle formulae.
*May 20, 2015*

**PHYSICS**

so, what are your calculations? Maybe we can figure out what's wrong.
*May 20, 2015*

**L A/The Giver**

I agree with #1 Have you read the other two books in the series? Good story.
*May 20, 2015*

**math**

If the loan is for 62 days, then you want just 62/360 of the 15% for interest, since it's 15% for a whole year. (assuming the 360-day year)
*May 20, 2015*

**math**

I assume you want just the region in QI, since otherwise the axis of rotation is inside part of the region. So, we want the area whose vertices are (0,0), (0,1) and (π/2,π/2) Around the x-axis, we have, using discs, v = ∫[0,π/2] π ((x+cosx)^2 - x^2) ...
*May 20, 2015*