Wednesday

October 26, 2016
Total # Posts: 45,305

**Pre-Calculus**

Draw your triangles and see that cosA = 4/5 sinB = 15/17

*October 6, 2016*

**math**

S is a collection of line segments with x- and y-intercepts at (0,1-t) and (t,0) Divide the interval (0,1) into n intervals of width 1/n. Then the two lines at t=k/n and t=(k+1)/n intersect at y = (n-k)(n-k-1)/n^2 So, adding the (k+1)st line adds a thin triangle of base 1/n ...

*October 6, 2016*

**Algebra**

35.00 + 7.25x = 29.00 + 10.50x

*October 6, 2016*

**Physics**

You must not have tried too hard, because I got several hits, such as https://answers.yahoo.com/question/index?qid=20070429182156AAn5Pem which is the exact same problem, but with different numbers.

*October 6, 2016*

**Physics**

try google first I saw several discussions of problems just like yours.

*October 6, 2016*

**calculus**

The distance z from (4,1) to (x,y) is z = √((x-4)^2 + (y-1)^2) = √((y^2/4 - 4)^2 + (y-1)^2) = (1/4)√(y^4-16y^2-32y+272) dz/dy = (1/2)(y^3-8y-8)/√(y^4-16y^2-32y+272) dz/dy=0 when y^3-8y-8=0 y = -2 or y = 1±√5 The minimum z is at y=1+√5...

*October 6, 2016*

**C++**

so, have you compiled and run it? does it do the job?

*October 6, 2016*

**science**

none of the above...

*October 6, 2016*

**Math**

(5/6 ft^2)/(1/2 hr) = (5/6)/(1/2) ft^2/hr = 5/3 ft^2/hr

*October 6, 2016*

**Math mystery number**

7 digits xxxxxxx digit in the ten thousands place is 9 ..9.... The digit in the thousands place is 5 ..95... Now we are down to vw95xyz The hundreds thousands place is the same as the tens place: y=w vw95xwz digit in the hundreds place is 3 times greater than the digit in the ...

*October 5, 2016*

**Algrebra and Math**

f+m = 32 f-1 = 2(m-1) 21 females 11 males check: Fran has 20 female classmates Billy has 10 male classmates

*October 5, 2016*

**Math**

use the Pythagorean Theorem. x^1 + 1^2 = 8^2

*October 5, 2016*

**math**

It looks good, but it's confusing having a club named x and also using x for the no. of months. So, it looks like a typo, but the functions are correct.

*October 5, 2016*

**Math**

you have three quantities: t,r,d and they give you some facts: t = 3r and so on. Then solve for the values.

*October 5, 2016*

**algebra**

(4 x 10^-5)^-6 = 4^-6 * 10^(-5*-6) = 1/4^6 * 10^30

*October 5, 2016*

**Engineering/Physics**

Power = Work/time = Force*distance/time The force, of course, is pressure*area Now just put things into the proper units and it all falls out.

*October 5, 2016*

**calculus**

(a) y(0) = ? (b) this is just a parabola. You know the vertex is at x = -b/2a (c) y=0 at x=? c'mon - don't forget your Algebra I now that you're taking calculus...

*October 5, 2016*

**Math**

dang! count the - signs (not the = signs!)

*October 5, 2016*

**Math**

10x = -5 has solution x = -0.5 -10x = -5 has solution x = 0.5 Now just count the = signs an odd number will be - an even number will be + (on the left side)

*October 5, 2016*

**Pre-Calculus**

clearly B is false at x=π Sec(x) / tan(x) = tan(x) / [tan(x) – cos(x)] (-1)/0 = 0/(0-(-1)) = 0/1 -∞ = 0 I don't think so!

*October 5, 2016*

**College Algebra**

And, note that this maximum area occurs when the fencing is equally split among lengths and widths.

*October 5, 2016*

**geometry**

h(t) = -16t^2 + 60t = 4t(-4t+15) h(2) = 4*2(-4*2+15) = 8(7) = 56 now just plug in 3.75 for t. Or, note that h(t) = 0 when -4t+15=0 t = 15/4 = 3.75 so, what does that mean?

*October 5, 2016*

**Math**

Divide the volume (L) by the net fill rate (L/min): 100/(60/5 - 14/2) = 20 min

*October 5, 2016*

**College Algebra**

look at the units. You have mi/gal mi/hr You want to use those to end up with miles in terms of hours. mi/hr * hr = mi d(t) = 65t mi/(mi/gal) = gal n(d) = d/25 d(t) is miles driven in t hours n(d) = gallons used in d miles = gallons used in t hours. (n◦d)(t) = n(65t) = ...

*October 5, 2016*

**maths polynomial need help**

(8m^2-24m-3+3√17)/4 * (8m^2-24m-3-3√17)/4

*October 5, 2016*

**math**

256πh/3 = 420 solve for h

*October 5, 2016*

**Enriched Geometry**

180° is 1/2 turn So, you have rotated it 100/2 = 50 complete turns. No change.

*October 5, 2016*

**Algebra 1 Honors**

yes

*October 5, 2016*

**math**

Must be a mistake. Your work looks right to me. Unless there is some fan overlap.

*October 5, 2016*

**astronomy**

1/8 = (1/2)^3 so, 3 half-lives have passed.

*October 5, 2016*

**precalc**

use what you know about hyperbolas. Since the center and vertices are bot at x=2, the axis is vertical. So, given the center, we have (y+3)^2/a^2 - (x-2)^2/b^2 = 1 However, you have garbled the foci. Since the center is at y = -3, the foci cannot be symmetric about the x-axis...

*October 5, 2016*

**precalc**

go to this url, and click the "properties" button, and see whether you can derive the values they give. If not, review the properties of hyperbolas. http://www.wolframalpha.com/input/?i=%E3%80%96(y%2B2)%E3%80%97%5E2%2F4-((%E3%80%96x%2B3)%E3%80%97%5E2)%2F49%3D1

*October 5, 2016*

**maths - mangled!**

and no graph

*October 5, 2016*

**maths**

no figure, no question.

*October 5, 2016*

**percentage**

% increase is the amount of increase, divided by the original value. In this case, the number x is increased by 10. If 20 is increased by 10, that is a 50% increase, since 10/20 = 0.50 If 40 is increased by 10, that is a 25% increase, since 10/40 = 0.25

*October 5, 2016*

**Math**

for the two tangent lines, where is 3x^2+1 = 4? x = ±1 y(1)=2 y(-1) = -2 So, the two lines are y-2 = 4(x-1) y+2 = 4(x+1) y" = 6x so, at x=0 the slope is smallest: 1 If you look at the graph, you can clearly see that the slope at x=0 is smaller than at x=1 or -1. ...

*October 5, 2016*

**math**

area: (50-12)(30-12) = 684 Now subtract that from the 50*30 original area to get the area of the strip.

*October 5, 2016*

**Aglebra, math**

Once a is all by itself, expressed in terms of the other values, the equation has been solved for a. That is not the case here, since a occurs on both sides of the equation.

*October 5, 2016*

**math**

Refer to your formulas: C = 2πr A = πr^2

*October 5, 2016*

**algebra**

(b+10)*20/2 = 240 Now just solve for b.

*October 4, 2016*

**Math**

how many 2-digit? 49 (51-99) how many 3-digit? ...

*October 4, 2016*

**math**

A = (b1+b2)h/2 (b1+b2)h = 2A b1+b2 = 2A/h b1 = 2A/h - b2 you forgot to multiply A by 2/h

*October 4, 2016*

**Math**

f(x) = ax^3+bx^2+cx+d f'(x) = 3ax^2+2bx+c f(1)=4 f(-1)=6 f'(1) = 13 f'(-1) = 1 So, rack 'em up and knock 'em down: a+b+c+d = 4 -a+b-c+d = 6 3a+2b+c = 13 3a-2b+c = 1 (a,b,c,d) = (4,3,-5,2) f(x) = 4x^3+3x^2-5x+2 See the graphs at http://www.wolframalpha.com/...

*October 4, 2016*

**math**

-4 + 2(30/5)

*October 4, 2016*

**Math**

monomial, degree 3

*October 4, 2016*

**adv function**

the remainder will always have degree less than the divisor. So, it will be of the form r(x)=(ax+b) So, you know that r(1)=1 r(3)=3 Now solve for a and b. As you surmised, the degree of p(x) does not really matter.

*October 4, 2016*

**Algebra**

factor out the common (x+2) and you have x(x+2)+3(x+2)+4x(x+2) = (x+3+4x)(x+2) ...

*October 4, 2016*

**Math**

much better. All correct.

*October 4, 2016*

**Math**

Since you have swimming on Tuesday diving on Friday how can they ever be together?

*October 4, 2016*

**Math @Victoria**

all probabilities are less than 1.

*October 4, 2016*

**Geometry**

C is 23 of the way from A to B A(-2,3) + (6,3) + = B(4,6) So, add 2/3 of (6,3), or (4,2) to A. A(-2,3) + (4,2) = C(2,5)

*October 4, 2016*

**Physics**

That's better

*October 4, 2016*

**Physics**

No, it takes 7 seconds to make the round trip. Stop guessing and start calculating.

*October 4, 2016*

**Math**

dunno (80+1)-(15+1) = 80-15 = 65

*October 4, 2016*

**maths need help**

google arcsinh to get the definition I gave google complex logarithm to find how to evaluate it. Surely you have enough keywords to do some research yourself. I didn't know that stuff either, but I know how to search for it.

*October 4, 2016*

**maths need help**

I'm sure you know that arcsinh(z) = log(z+√(1+z^2)) so, arcsinh(2+i) = log(2+i + √(4+2i)) = log(4.058 + 1.486i) Now log(z) = log(x+yi) = log(√(x^2+y^2) + i arctan(y/x) So, plug in your z value above and crank it out.

*October 4, 2016*

**please help math**

if x is at 12%, then the rest (9500-x) is at 7%. so, add up the interest for each part. The sum must be 960.00

*October 4, 2016*

**maths-need help**

well, you know that e^0 = 1 as for the other root, a graphical or numeric method must be used. The graphs here will get you started. http://www.wolframalpha.com/input/?i=e%5Ex+%3D+2x%2B1

*October 4, 2016*

**Meth**

these just have to be covered in your text. Look up supplementary, complementary, vertical, parallel

*October 4, 2016*

**math**

2(w + w+70) = 380

*October 4, 2016*

**Physics**

after t seconds, v = 55.0 - 2.5t So, it takes 55.0/2.5 seconds to stop In that time, the jet travels s = 55.0t - 1.25t^2 meters Plug in your value for t and see whether s <= 600

*October 4, 2016*

**M.A.T.H.**

or, since 1 * anything = the same, 1 * -1 = -1 (+) * (-) = (-)

*October 4, 2016*

**Physics**

yes -- velocity = speed. Look at the units: (m/s^2)*(s) = (m/s) acceleration is how much the speed changes each second: (m/s)/s = m/s^2 so, in your example, the speed grows by 80m/s every second. quantity = rate * time, such as 5 pages/day * 2 days = 10 pages etc.

*October 4, 2016*

**Physics**

v = at plug in your numbers. watch the units.

*October 4, 2016*

**Adv functions**

you omitted the value of the root it has, as well as the function itself.

*October 4, 2016*

**Math adv function**

If you divide by a cubic polynomial, the remainder will be a quadratic, r(x) = ax^2+bx+c Now, you know that r(1) = 1 r(3) = 3 r(5) = 21 a+b+c = 1 9a+3b+c = 3 25a+5b+c = 21 r(x) = 2x^2-7x+6

*October 4, 2016*

**Math**

what does it mean to be supplementary? If one angle is x, then what is the other?

*October 4, 2016*

**Math**

it is already a ratio, just not in lowest terms. You can reduce it by dividing each term by 64.

*October 4, 2016*

**algebra**

just substitute in 30 for x and evaluate the number.

*October 4, 2016*

**Algebra**

no. 0.45 = 45/99 reduce that 1/45 = 0.022222... as you could easily have checked on your calculator. geez.

*October 4, 2016*

**Math**

see the postings by "Drake" and "Alys" >wink wink<

*October 4, 2016*

**Math**

how much has the price changed? what percent of the original price is that?

*October 4, 2016*

**Math**

not even close how much has the price decreased? what percentage of 8999 is that?

*October 4, 2016*

**math**

Since distance = speed * time, 210+105(t-2) = 135(t-2) t=9, so the distance = 7*135 = 945 mi or, since the time is the same once both trains are moving, if the distance each has traveled is d, (d-210)/105 = d/135 d = 945

*October 4, 2016*

**Geometry**

a plane has two dimensions a line has one Any point on the number line can be designated by a single number. Any point in the plane requires two coordinates: one on each number line serving as the axes.

*October 4, 2016*

**percentage**

What I don't understand is how two distinct numbers, operated on in identical ways, produce the same result... I think the question is mangled.

*October 4, 2016*

**glen view**

depends on how wide it is. then recall that volume is length*width*depth

*October 4, 2016*

**percentage**

if the pass mark is p, then if Ram attempted x questions, then Shyam attempted (100-x) questions. So, 2(.7x)-1(.3x) = p+40 2(.6(100-x))-1(.4(100-x)) = p+25 now just solve for p.

*October 4, 2016*

**Algebra 1**

start writing the data as math. Let the number of bills (1,5,10,20) be w,x,y,z. Then w+x+y+z = 25 w = 2y ... You will wind up with 4 equations to solve for w,x,y,z.

*October 4, 2016*

**Physics**

since density = mass/volume, volume = mass/density watch the units: (kg) / (kg/m^3) = m^3

*October 4, 2016*

**physics**

is the puck sliding?

*October 4, 2016*

**percentage**

so, what is the pass mark?

*October 4, 2016*

**Very Urgent Help Here (Math)**

Each shell has thickness dy, so its volume is 2πrh dy. Add them all up and you have v = ∫[0,1] 2πrh dy where r=y and h=x=√(1-y) v = ∫[0,1] 2πy√(1-y) dy = 8π/15 As a check, using discs, v = ∫[0,1] πr^2 dx where r=y=(1-x^2) ...

*October 3, 2016*

**math**

If you have angle AOB and want to construct BOC such that AOB and BOC are congruent, with the compass draw an arc subtended by AOB and extending beyond OB. Let the arc intersect OA at D and OB at E. Place the compass at E and set to the distance ED. Then draw a circle with ...

*October 3, 2016*

**Calculus**

it could be a linear function yield = k * fertilizer + some_minimal_yield or it could be more complicated.

*October 3, 2016*

**Math**

add up the amount for one of each coin. 46.20 will be a multiple of that amount.

*October 3, 2016*

**MATH! HELP PLEASE!**

list the pairs of factors of 24 1x24 2x12 etc.

*October 3, 2016*

**Math**

40.8/8 in each "contain"

*October 3, 2016*

**Math**

there are 10^4 4-digit integers there are P(10,4) with no repeats divide P(10,4)/10^4 for the probability of no repeats. You want 1 minus that probability. 1 - P(10,4)/10^4 = 62/125 so, almost 50%

*October 3, 2016*

**math**

you're right - you do need help...

*October 3, 2016*

**Algebra**

The area is length * width: (2x+5)(8) = 16x+40 Use that in B, and then solve for x if 16x+40 = 160

*October 3, 2016*

**Math adv functions**

a little synthetic division shows that it is not. However, it is a factor of x^9+5b^2x^7+5bx^8+b^9

*October 3, 2016*

**Math**

Start a table of the powers of 11 n 11^n 1 11 2 121 3 1331 4 14641 The last 2 digits just cycle through 11 21 31 ... 91 01 11 21 ... So, 11^2016 ends in 61 Or, you might find this article on modular arithmetic useful: https://www.khanacademy.org/computing/computer-science/...

*October 3, 2016*

**science**

what do you think? If you toss in something light, like a cotton ball, does it float or sink?

*October 3, 2016*

**math**

y = a√x + bx y' = a/(2√x) + b Since the normal at x=1 has slope 1, the tangent has slope -1. So, y'(1) = a/2 + b = -1 b = -(a+2)/2 y(1) = a - (a+2)/2 = (a-2)/2 The normal line through (1,(a-2)/2) is thus y-(a-2)/2 = 1(x-1) This passes through (0,-14), so -...

*October 3, 2016*

**math**

is the : supposed to be division? If so, 1/(-1) + 0/4 - (-4)x(-1) = -1 + 0 - 4 = -5

*October 3, 2016*

**Math**

uhhh, that's what I did, right?

*October 3, 2016*

**Math**

you can approximate it using logs log(11^2016) = 2016 * log11 = 2016*1.04139 = 2099.4476 so, 11^2016 ≈ 2.80319 * 10^2099 the exact value is at http://www.wolframalpha.com/input/?i=11%5E2016

*October 3, 2016*

**Math**

you're welcome. Tricky problem, and easy to misinterpret, as I showed.

*October 3, 2016*

**Math**

You are right. They started out as 99% water, so there was .99 * 16 = 15.84 lbs water .01 * 16 = 0.16 lbs flesh When they have dropped to 80% water, the 0.16 lbs flesh is still there, but it is now 20% of the weight. So, 0.16 = 0.20x x = 0.8 so, the cucumbers now weigh 0.8 lbs.

*October 3, 2016*