Monday
May 4, 2015

Posts by Steve


Total # Posts: 31,021

Maths
1 - (4/9 + (2/5)(5/9)) = 1/3
March 31, 2015

Maths
2/5 rotten means 3/5 fresh 3/5 * 5/8 = 3/8 kg
March 31, 2015

This is nothing to do with school
3a+c = 30 a+3c = 22 take it from there...
March 31, 2015

ABC
drop the stone and time how long it takes to hit the ground. Actually, that does not measure the height of the building. He infers the height from the time taken. To actually measure the height, he'd probably have to measure the width of the stone and then count how many ...
March 31, 2015

science
Vx = 9.8 Vy = √(2as) = √(2*9.8*100) = 44.27 final v = √(Vx^2 + Vy^2)
March 31, 2015

calculus
cos2x = secx 2cos^2(x)-1 = 1/cosx 2cos^3(x) - cosx - 1 = 0 you will probably need to use a graphical or numeric method to solve this. However, you know that cos2x never gets more than 1, and secx never gets less than 1. So, you will need cos2x = secx = 1 or cos2x = secx = -1 ...
March 31, 2015

Algebra
(a) look good (b) the friend
March 31, 2015

algebra
since x is proportional to y, x = ky That is, x/y is constant. So, 12/16 = 1/y
March 31, 2015

chemistry
well, PV = nRT plug in your numbers and solve for P.
March 30, 2015

Calculus
profit = revenue-cost revenue = 20*4πr^2 = 80πr^2 cost = 800*4/3 πr^3 = 3200/3 πr^3 so, profit = 80πr^2 - 3200/3 πr^3 max profit when 160πr - 3200πr^2 = 0 160πr(1-20r) = 0 r = 1/20 ft looks like marbles make the most money.
March 30, 2015

math
24*72 = 24*3*24 = 3*24^2 so, its root is 24*root(3)
March 30, 2015

5th grade (math)
no idea. How big is the lawn?
March 30, 2015

English
my answer is B
March 30, 2015

English
Which of the following moments in "The Most dangerous Game" represents an example of foreshadowing? a-Whitney & Rainsford';s discussion about hunting b- Rainsford's observing the gate of the chateau c- Whitney's comment about the light of Rio?
March 30, 2015

math
see some of the related questions below.
March 30, 2015

math - eh?
How did Kayla give away 3/2 beads? Try posting the question as you received it.
March 30, 2015

Calc.
I must be missing something. Clearly the minimum length of fold is achieved when the paper is folded in half, so the upper right corner touches the lower right corner. Then the fold is straight across, and is 8" long. Any diagonal fold will be longer. Of course, I have no...
March 30, 2015

Calculus
If the distance is x from P, then the cost is c(x) = 1.5√(x^2+25) + (10-x) dc/dx = 1.5x/√(x^2+25) - 1 = [1.5x - √(x^2+25)]/√(x^2+25) dc/dx=0 when the numerator is zero, or 1.5x = √(x^2+25) 2.25x^2 = x^2+25 1.25x^2 = 25 x^2 = 20 x = 2√5
March 30, 2015

Algebra
(r^-3s^1/3)^6 / (r^7 s^3/2) r^-18s^2 /(r^7 s^3/2) r^-11 s^1/2 or s^1/2 / r^11
March 30, 2015

Algebra 2
#1 add the two equations to eliminate y^2: 2x^2=18 x = ±3 #2 multiply by 3 to get 3x^2+3y^2=24 since 3x^2 = 5y^2, 8y^2 = 24 y^2 = 3 #3 just sub in directly: 3x^2-2y^2 = 24 3x^2 - (1/2)(2y)^2 = 24 3x^2 - (1/2)(3x)^2 = 24 6x^2 + 9x^2 = 48 15x^2 = 48 x^2 = 16/5
March 30, 2015

Algebra HELP ASAP
w(2w-1)=10 2w^2-w-10 = 0 (2w-5)(w+2) = 0 w = 5/2 so, the length is 4
March 30, 2015

calculus
the distance from (x,y) to (4,-3) is √((x-4)^2 + (y+3)^2) = √((x-4)^2 + ((2x+7)/4+3)^2) = √5/4 (4x^2-20x+61) This has a minimum at x = 37/10 So, the point is (37/10,-18/5) Or, you can consider the perpendicular line through (4,-3). It is y+3 = 2 (x-4) This ...
March 30, 2015

algebra
42
March 30, 2015

Math
1x10^-2 = 1/100 lbs = 4/25 oz seems a bit light, but it's a lot closer than 10^-20 = 1/100000000000000000000 lbs!!!
March 30, 2015

calc
f is increasing where f' > 0 since the even powers are always positive, f'>0 where x-3 > 0 and x-4 > 0 so, that would be (3,4)U(4,∞)
March 30, 2015

Middle Math
Nope. too many zeros, and wrong number 6E0 = 6 6E-1 = 0.6 ... 6E-7 = 0.0000006 You wrote 7E-8
March 30, 2015

math
if the discriminant is zero, there is only one root, hence only one point of intersection. positive, two roots negative zero roots Incidentally, you'd better check your discriminant. If you graph y=x+5, you will see that it intersects in two points, not 1. http://www....
March 30, 2015

calculus
see the related questions below
March 30, 2015

Math
y = x^(e^x) lny = e^x lnx 1/y y' = e^x(lnx + 1/x) y' = x^e^x * e^x (lnx + 1/x)
March 30, 2015

Calculus
you have the functions. Just plug in the values.
March 30, 2015

Calc
(a) dC/dx (b) and (c) are just plug and chug
March 30, 2015

math help
come on. You have the formula. Just solve n^2+n-1 = 2549 Hint: it's not -51
March 30, 2015

math help
check the differences: 4,6,8 I suspect that the next terms are 19+10=29 and 29+12 = 41 you plug in 3 pairs of values into a general quadratic y=ax^2+bx+c and you get a+b+c=1 4a+2b+c=5 9a+3b+c=11 a=1, b=1, c=-1 and get Tn = f(n) = x^2+x-1 Or, you can recall that 1+2+3+...n = n(...
March 30, 2015

Mathematics
((5*.60)+.80)/6 = 63.3% You didn't say whether the tests were weighted, so I'm not sure what the 200 points mean.
March 30, 2015

Algebra
after t minutes, you want 30+25t = 300-20t
March 30, 2015

Algebra 1
Find the solution to the system y=x^2-2x-2 My answer is (-1,1)(7,33)
March 30, 2015

Calculus
well, um, did you try actually drawing the graphs? x=4√y is the right half of a parabola that opens upward y=4√x is the upper half of a parabola that opens to the right. You can think of it as the area in the 1st quadrant, bounded by y=x^2/16 and x=y^2/16 You have ...
March 30, 2015

Math
3 choices for each of 10 questions is clearly 3^10 Naturally, there is only 1 way of getting all the answers right. If, however, you want to know the order of questions to answer, then there are 10! ways to select the questions. Rather a poorly worded question.
March 30, 2015

algebra
the difference in heights is 5, so the distance between the tops is the hypotenuse of a 5-12-13 right triangle.
March 30, 2015

Math
3*4*4, no?
March 30, 2015

exponential equations
Since 6400 is 16 * 400, the population has doubled 4 times. So, it will take 4*18 minutes.
March 29, 2015

maths
think of the shape of a wine glass. It's basically a parabola. Not sure what you will do with the linear, since you need a vertical stem and a horizontal base. How about y=0 y=x^2+4 with a suitable domain
March 29, 2015

Algebra
12 ft^2, but it won't hold much water.
March 29, 2015

arcsin?
Hmmm. I get tan^-1 (x/3)
March 29, 2015

science
it's just ∑mv for all the various m and v: 1300(60) + 1500(-95)
March 29, 2015

basic math
well 66 2/3 percent is 2/3, or 66.67% Simple or compound interest? 66.67% seems a bit high.
March 29, 2015

English
thank you
March 29, 2015

English
And if we meet we shall not ’scape a brawl, For now, these hot days, is the mad blood stirring. the fight in which Mercutio and Tybalt are killed or the duel in which Romeo is killed my answer is the 1st one because it was a fight
March 29, 2015

English
Death lies on her like an untimely frost Upon the sweetest flower of all the field. (Act 4, Scene 5) ow Does this example of dramatic irony create tension? My answer is because the reader know that Juliet is actually sleeping
March 29, 2015

Calculus
you know that ∫ du/√(a^2-u^2) = arcsin(u/a)+C right? So, just note that 8+2x-x^2 = 9-(x-1)^2 Now go for it.
March 29, 2015

English
I think that it is the last one.
March 29, 2015

English
Marry my child early next morn the gallant young and noble gentleman the county paris at st peter church shall happily make thee there a joyful bride Hang thee, young baggage! Disobedient wretch! I tell thee what: get thee to church o' Thursday, Or never after look me in ...
March 29, 2015

English
What quote from Romeo and Juliet Act 3, Scene 5 illustrates Shakespeare's use of comic relief?
March 29, 2015

Calculus
since cos(u) < 1, your terms are less than 1/(2^(k/3)+1) sum 1/2^(k/3) converges, and your terms are less than 1/2^(k+3), your series converges
March 29, 2015

English
thank you
March 29, 2015

English
Read the following line from Act IV, Scene 5 of Romeo and Juliet, when Capulet speaks of his daughters apparent death: Death lies on her like an untimely frost Upon the sweetest flower of all the field. How does Shakespeare use a simile to emphasize the tragedy of the apparent...
March 29, 2015

math
a = bh/2 135 = b*15/2 ...
March 29, 2015

Calculus 2 - Series
yeah - sometimes it's possible to overthink this stuff. It just takes practice, like anything else. Good judgment comes from experience. Experience comes from bad judgment.
March 29, 2015

Calculus 2 - Series
an = (n + 3)/(2n − 1) well, just start plugging in values for n: a1 = (1+3)/(2*1-1) = 4/1 = 4 a2 = (2+3)/(2*2-1) = 5/3 and so on ... Look at the numerators: 3,4,5,... = n+2 and the denominators: 4,9,16,... (n+1)^2 So, an = (n+2)/(n+1)^2
March 29, 2015

Pre Ap Chemistry
since PV/T = k is constant, (.825)(566)/(273+15) = P(834)/(273+20)
March 29, 2015

Calculus 2 (Differentiate & Decay Problem)
#1 you don't have to differentiate. You are given the differentials, and you need to integrate 8sin^2(y) dx + 8cos^2(x) dy = 0 cos^2(x) dy = - sin^2(y) dx dy/sin^2(y) = -dx/cos^2(dx) -csc^2(y) dy = sec^2(x) dx now integrate: cot(y) = tan(x) + c now, since (π/4,π/...
March 29, 2015

Math
sinC/c = sinA/a sinC = 6.1*0.342/2.1 = 0.993 That is so close to 1, I'd say C=90° So, yes, you are correct. Just a single right triangle does the trick.
March 29, 2015

Algebra 1
Find the measure of the smallest angle of the right triangle. c= 90degree a= height ac= 7 and cb = 11 a-32.5 degree b-57.5 degree c-13.0 degree d-50.5 degree my answer is a 32.5 degrees
March 29, 2015

Calculus
a = πr^2 da/dt = 2πr dr/dt So, plug in your numbers. When a = 4π, r=2, so 2 = 2π*2 dr/dt dr/dt = 1/(2π) miles/day
March 29, 2015

Math
yeah - compound or simple!
March 29, 2015

Math
the problem will tell you which it is. Although, if it neglects to say the compounding period, it is most likely simple interest.
March 29, 2015

Algebra 1
thank you
March 29, 2015

Algebra 1
If the leg of length 11 is adjacent to angle a, you are correct.
March 29, 2015

Algebra 1
In a right triangle c=90 degrees a=52 degrees b = 38 degrees the base length =11 What is the hypotenuse length? a-6.8 b-8.7 c-14.0 d-17.9 my answer is 17.9 d
March 29, 2015

Algebra 1
x=1 does satisfy the equation.
March 29, 2015

Algebra 1
Solve for x sq root 2x+3= sq root 6x-1 a-1 b-2 c-3 dsq root 6 My answer is a = 1
March 29, 2015

Algebra 1
correct
March 29, 2015

Algebra 1
A right triangles hypotenuse is 20 cm long. What is themlength of the side opposite a 60 degree angle? a- 40 b- 18.5 c- 20 d- 17.3 My answer is 17.3
March 29, 2015

Algebra 1
In a right triangle the height = 54 (ba) The hypotenuse is 90 (ac) and the base ism 72 (bc). What is the value of cosC? a-.5 b- .6 c- .8 d- .9 My answer is .8 72/90
March 29, 2015

Geometry
2(w + w+40) = 500
March 29, 2015

integral calculus
just apply the power rule to each term ∫ x^n dx = 1/(n+1) x^(n+1) so, ∫ x^4 dx = 1/5 x^5 and similarly for the other terms
March 29, 2015

math
each face is a triangle with base 8 and altitude 22
March 29, 2015

ALGEBRA
clearly the compound inequality is an and problem. As for absolute value problems, think of the shape of the graph. It is a V shape. So, if |f(x)| < c, you have one interval, below the line y=c. If |f(x)| > c, then you have the intervals outside the V, making it an or ...
March 29, 2015

maths
if they are in series, then R = 2+3+r If they are in parallel, then 1/R = 1/2 + 1/3 + 1/r
March 29, 2015

math
9-m^2 = (3-m)(3+m) So, the (3-m) factors cancel, and you have (3+m) in the top. Not sure just what the other stuff means; your use of numbers and carets is inconsistent. Just recall that u^n/u^m = u^(n-m) whatever u is.
March 29, 2015

Math
the distance z between you and Jonas after t seconds is z^2 = (60-2t)^2 + (10t)^2 For the box, we know xyz = 500000 since y=2x, 2x^2z = 500000 x^2z = 250000 So, z = 250000/x^2 c(x) = (x)(2x)(3) + (6x)(250000/x^2)(4) + (x)(2x)(5) = 16x^2 + 6000000/x Now just do your minimum stuff.
March 28, 2015

Math
I went back and checked my figures and I think it should be a t sq root 26
March 28, 2015

Math
A playground is shaped like a rectangle with a width 5 times it's length (t). What is the simplified expression for the distance between opposite corners of the playground? a- tsq root 26 b- 5t c- 26t squared d- 6t my answer is d 5t 5t+t =x x=6t
March 28, 2015

Math
Simplify 6/sq root 3 +2 My answer is 12 - 6 sq root 3
March 28, 2015

Math
thank you
March 28, 2015

Math
A surfer drives his dune buggy out into the sand dunes.He follows his compass 10 miles due north and then turns due west. If he ends up approximately 35 miles from where he started how far west did he travel? a- 10 miles b- 25 miles c- 33.5 miles d- 35 miles My answer is c 33....
March 28, 2015

Math--MS SUE!
#1 24 #2 46 #3 70
March 28, 2015

Math
Good job, Reiny. I keep seeing 3^√ being used as cube root, so maybe I was way off. In any case, the problem is solved.
March 28, 2015

Math
let f(x) = x^3 - 7 so f(∛7) = 0 See http://keisan.casio.com/exec/system/1244946907 just enter your function, its derivative, and initial guess.
March 28, 2015

Earth Space Science
you are correct.
March 28, 2015

statistics
so, do you have a table of NBA players' heights? If so, just do what the exercise says.
March 28, 2015

Math
I get XB=6 How far do you get? Hint: parallel lines indicate similar triangles.
March 28, 2015

Trigonometry
Usage differs, but one of them is the single value -π/3, and the other is -π/3+nπ check your text to see what is expected of you.
March 28, 2015

Trigonometry
just factor the first one, then there will be two values between 0 and 2π, and all multiples of 2π added thereto. 2sin^2(x)-5 sin(x)-3=0 (2sinx+1)(sinx-3) = 0 sinx = -1/2 sinx = 3 (not a valid solution) The other is already factored: (cos(x)-((√2)/2))(sec(x)-1...
March 28, 2015

Trigonometry
tan(-π/4) = -1 so, θ = -π/4 + nπ sin(π/6) = 1/2, so θ/2 = π/6,5π/6,... θ = π/3, 5π/3, ... = π/3 + 4nπ, 5π/3 + 4nπ
March 28, 2015

Trigonometry
(2sinx-√3)(2sinx+√3) = 0 sinx = ±√3/2 x = π/3, 2π/3, 4π/3, 5π/3 cos(3x) = -1 so 3x = π,3π,5π x = π/3, π, 5π/3
March 28, 2015

Math
my answer is D
March 28, 2015

Math
A gardener is mowing a 20 by 40 yard rectangular pasture using a rectangular pattern. He mows from one corner of the pasture to the corner diagonally opposite. What is the length of this pass with the mower? Give your answer in simplified ,form. a- 10 sq root 20 b- 20 sq root ...
March 28, 2015

math
2x*5x = 40 So, find x, and then 5x.
March 27, 2015

math
f(x) = 2(x-1)^2 - 7 So, if we restrict the domain to x>1 or x<1 we can find an inverse I expect you can turn that info into an interval . . .
March 27, 2015

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