Thursday

July 28, 2016
Total # Posts: 42,148

**Algebra II**

b^2 = 81-25 find the angles using your standard trig functions; you have all three sides.
*May 19, 2016*

**Pre Algebra**

I'll do #1 -- the others you can do the same way, and we can check your answers. Just use the distributive property and the commutative properties. 18x^2+4x-15x^2-4+13x = 18x^2-15x^2 + 4x+13x - 4 = (18-15)x^2 + (4+13)x - 4 = 3x^2 + 17x - 4
*May 19, 2016*

**Please answer these questions Algebra 1**

#18 x^2-4x+1 = 0 x = (4±√20)/2 = 2±√5 #19 Hmmm. You don't say what models you have been using. Arranging the points from left to right, we have x y ------ -3 3 -2 0 -1 -1 0 0 1 3 The symmetry makes me want to try a quadratic with vertex at (-1,-1...
*May 19, 2016*

**Math -rational exponents**

root(3,12m^2) Not sure why you have two arguments to root. Do you mean cube root? If so, then you just have 12^(1/3) m^(2/3) Then nth-root is just the (1/n) power. Plug it in and then just use the normal exponent operations.
*May 19, 2016*

**math**

you are correct.
*May 19, 2016*

**math**

gee, impatient much? You are incorrect. Of the 9 tosses, how many are odd? You must have miscounted.
*May 19, 2016*

**Math - correction**

I misread the problem. If we label the bottom of the pole B, then BT cot68 = (BT-20) cot28 Both those expressions give BP, the distance between the building and the pole. To get PT, then, PT^2 = BP^2 + BT^2
*May 19, 2016*

**Math**

draw a diagram. Review your basic trig functions. PT cot68 = (PT-20) cot28
*May 19, 2016*

**math**

correct.
*May 19, 2016*

**math**

That would just be 1.43/1.09 * 10^(15-12)
*May 19, 2016*

**Math**

The equation is incorrect. Fix it and balance it.
*May 19, 2016*

**Math**

50+60+70-24-x = 100 Draw your Venn diagram to see why.
*May 19, 2016*

**Math**

actually, that should be 3x
*May 19, 2016*

**Math**

70+30+50-44-x = 100
*May 19, 2016*

**2nd year Spanish**

looks good to me.
*May 19, 2016*

**Math**

all look good
*May 19, 2016*

**Math Help- Areas!!!!**

assuming the width is the diameter, then the radius is half that. Since a = 2πr(r+h), that gives 350π and 522π
*May 19, 2016*

**Algebra**

x^2+y^2 = 3xy-20
*May 19, 2016*

**Math**

It is certainly possible, but by no means necessary. The IVT only applies to continuous functions, and money comes in discrete steps. Ellie might have gone from having $102.37 to only having $93.18, depending on what she bought. Or, she might have spent $195 on one item, and ...
*May 19, 2016*

**Math**

why guess? Do the math. Looks like you knew what was going on. All three are correct.
*May 19, 2016*

**trigonometry**

you have x = 4 y = -2 r = √20 sinA = y/r = -2/√20 = -2/(2√5) = -1/√5 = -√5/5 cosA = x/r = 4/√20 = 4/(2√5) = 2/√5 = 2√5/5 tanA = y/x = -2/4
*May 19, 2016*

**math**

so, in other words,any number except 5 or 6. How many of those are there?
*May 19, 2016*

**Math**

well, what is the largest perfect square less than 800? √800 = 28.28 28^2 = 784 800-784 = 16
*May 19, 2016*

**MATH**

1.06p = 42.40
*May 18, 2016*

**math**

looks like Tn+1 = 2Tn + 2 so, write down the next few terms
*May 18, 2016*

**math**

what are the most common integer-sided triangles? 3 4 5 5 12 13 and their multiples.
*May 18, 2016*

**MATH**

4(x+1)(x+2) = 24 even without solving the equation, you know that (x+1)(x+2) = 6 so, what two consecutive numbers multiply to 6?
*May 18, 2016*

**math**

2(x-3 + 4) = 40
*May 18, 2016*

**help algebra??**

#1 - the probability is the same on every draw, since no names are removed when drawing: 80/400 and that's "principal." #2 (x-2+4)^2 + (y+1-6)^2 = 16
*May 18, 2016*

**MATH**

a quotient is less than one if the numerator is less than the denominator. So, is 5/6 < 7/8 ?
*May 18, 2016*

**Math**

x and 2x-17
*May 18, 2016*

**Math**

The global competition for the World Cup is broken into six continental zones. The number of teams in Scottish teams zone is 17 less than twice the number of the teams in the Puerto Rican teams zone. How many teams are in each zone?
*May 18, 2016*

**math**

total of 1st set is 12*5.5 total of 2nd set is 8k total of two sets is 20*8.5 so, you have 12*5.5 + 8k = 20*8.5 k = 13
*May 18, 2016*

**Math**

clearly not just the average, since that would be 5.5, or slower than Holly by herself. You have to consider how much works gets done in 1 hour by each person. Then you can add that up to see how much gets done together. 1/5 + 1/6 = 11/30 so, the paper takes 30/11 hours for ...
*May 18, 2016*

**calculus**

a little algebra. You didn't get that? Show whatcha got.
*May 18, 2016*

**calculus**

oops. That should have been ln y = 2lnx + 2x - ln3 - 1/2 ln(2x-5) and also 4x^2-7x-10 in the numerator
*May 18, 2016*

**calculus**

I assume you mean y = [x^2 e^(2x)]/ [3√(2x-5)] ln y = 2lnx + 2x - 3/2 ln(2x-5) 1/y y' = 2/x + 2 - 3/(2x-5) 1/y y' = (4x^2-9x-10)/[x(2x-5)] y' = [x^2 e^(2x)]/ [3√(2x-5)] * (4x^2-9x-10)/[x(2x-5)] x e^(2x) (4x^2-7x-10) ---------------------------- &...
*May 18, 2016*

**Geometry**

V/v = (R/r)^2 * H/h Not clear just what that ratio is; you garbled the problem.
*May 18, 2016*

**Math**

just as a hint, there are 4*2 possible ways to pick the outfit. How many of those have matching colors?
*May 18, 2016*

**physics**

could be, but I think there should be a t in there somewhere.
*May 18, 2016*

**maths**

the series is the sequence of partial sums. So, the first three terms are 1,5,13 No idea what the last term is, since I don't see a pattern to the items.
*May 18, 2016*

**Algebra I**

it means that the change does not depend on the amount already present. The amount changes by a constant amount each time period. That is, a fixed amount per year, per day, etc. So, what do you think?
*May 18, 2016*

**maths**

a(r^4-1)/(r-1) = 10 T4/T3 = 1/2 the common ratio is the ratio between any term and the previous one. That should get you started.
*May 18, 2016*

**Math**

3*3 = 9
*May 18, 2016*

**Math**

there are 3 entrees and 3 veggies. So, since you can pick any entree, and the match it with any veggie, what do you think?
*May 18, 2016*

**Math**

false -3 is not a natural number
*May 18, 2016*

**Math**

don't know about profit, but the revenue is price * quantity. So, r(x) = 1500x if x <= 150 x(1500-5(x-150)) if x > 150 This is just a parabola with vertex at (225,253125), which is clearly greater than the flat rate for groups of less than 150.
*May 18, 2016*

**Math! Please Check Answers!**

I like B, but doesn't a cube have 6 sides?
*May 18, 2016*

**Math**

you are correct
*May 18, 2016*

**Math**

I assume you know how to find the area of a right triangle. The volume is just base_area * prism_height.
*May 18, 2016*

**Calculus**

dx/dt = x^2 Hmmm. if x>1, this will blow up in a hurry
*May 18, 2016*

**Math**

Which survey question is biased? “Should the President of the United States serve a six-year term “Which meal—breakfast, lunch, or dinner—is your favorite meal of the day?” “During which month do you prefer to go on vacation?” “Do you ...
*May 18, 2016*

**Calculus**

y" = sin(x)+e^(2x) this should be no trouble. Just integrate twice and use the initial conditions to find the two constants.
*May 18, 2016*

**Math**

each side is √225
*May 18, 2016*

**Calculus**

well, dy/dx = √x/2y 2y dy = √x dx ...
*May 18, 2016*

**Algebra 2 help plsss?**

√1296 = 36, so assuming you meant 4√(1296 x^16 y^12) = 4*36x^8y^6 = 144 x^8 y^6 #2 come on. √4 = 2 (4-x)/(x^2+5x-6) ------------------------- = -(x+1)/((x-1)(x-7)) (x^2-11x+28)/(x^2+7x+6)
*May 18, 2016*

**Geometry/math**

v = pi r^2 h plug in your numbers
*May 18, 2016*

**Calculus**

dx/dy = e^(x+y) dx/dy = e^x * e^y e^-x dx = e^y dy -e^-x = e^y + c x(1) = 0, so 0 = e+c c = -e -e^-x = e^y - e e^-x = e - e^y x = -ln(e - e^y)
*May 18, 2016*

**Math (Check)**

me too
*May 18, 2016*

**Geometry**

pi * 3^2 * 2
*May 18, 2016*

**Geometry**

since (3,0) is on the x-axis, the angle there must be the one bisected by the axis. So, the 3rd vertex is at (6,-4). Now you can find the side lengths and thus the perimeter.
*May 18, 2016*

**math**

1680wd/20min = 84wd/min 84/80 = 1.05 or a 5% increase in speed.
*May 18, 2016*

**math**

well, 78-8 = 70 ...
*May 18, 2016*

**Mathematics**

when you say subtracted by do you mean x-150 or 150-x ? Pick one and set it equal to x/7, then solve for x.
*May 18, 2016*

**math**

Assuming you mean that the edge of the cloth is to be trimmed with lace, you want the arc length of the graph. ds^2 = (3cos^2(t)sin(t))^2 + (3sin^2(t)cos(t))^2 dt = 9sin(t)cos(t)(cos(t)+sin(t)) dt integrate that from 0 to pi/2 and multiply that by 4 to get the entire length of...
*May 18, 2016*

**math**

4*7
*May 18, 2016*

**math**

each term is -2 times the previous one.
*May 18, 2016*

**math**

64.1*10^6 / 54*10^4 = 1.19*10^2 = 119 people/mi^2
*May 18, 2016*

**math**

start at 8 each term adds 0.5
*May 18, 2016*

**math**

B and C are both trinomials. Typo?
*May 18, 2016*

**Math**

all the numbers from 1-9 can be formed from the 1st five terms. All multiples of 10 can be formed from the geometric terms (basically just a scaled binary sequence). With that, all the gaps between the tens can be filled with the units.
*May 17, 2016*

**Math (pre-celc 12)**

why would you add denominators? These are still just fractions. 1/x = x/(3x+18) multiply by x(3x+18) 3x+18 = x^2 ...
*May 17, 2016*

**ms sue?**

.22 + .46 - .10 = .58
*May 17, 2016*

**Algebra 1**

The first thing I'd do is multiply by 3 to clear all the fractions: 4s - 9 < 3s + 2 - s 4s - 9 < 2s + 2 2s < 11 s < 11/2
*May 17, 2016*

**integral calculus**

∫[0,2] 5x - 5x^2/2 dx
*May 17, 2016*

**calc**

3ln2 = ln 2^3 = ln8 by definition, e^lnx = x ln(e^x) = x ln and e^ are inverse functions
*May 17, 2016*

**calc**

ln(1/25) = ln(5^-2) = -2 ln(5) e^(3ln2) = e^(ln8) = 8
*May 17, 2016*

**Calculus question ?**

nope - just a vertical one
*May 17, 2016*

**word problem math**

forget all those decimal points. p+n+d = 9 p+5n+10d = 53 n = d-2 now just solve for p.
*May 17, 2016*

**math**

a = kbh a/bh is constant, so you want a such that a/(20*15) = 200/(25*16)
*May 17, 2016*

**Grade 12 Calculus and Vectors**

If the dimensions are x and y, then xy = 432, so y = 432/x If the shared side is y, then the cost for our homeowner is c = 2x + y + y/2 = 2x + 3/2 y = 2x + 648/x we want minimum cost, so dc/dx = 2 - 648/x^2 dc/dx = 0 when x = 18 So, the garden is 18x24, with the 24' side ...
*May 17, 2016*

**Algebra II**

a 90° clockwise rotation takes (x,y) -> (y,-x) review your rotation matrix definition.
*May 17, 2016*

**Geometry**

no idea. what is the relation between the two figures?
*May 17, 2016*

**Math/algebra**

what about the formula do you not understand? There are many handy online calculators that you can use to check your answer.
*May 17, 2016*

**maths**

2sin(180°+x)sin(90°+x)/cos^4x-sin^4x 2(-sinx)(cosx)/(cos^2x-sin^2x)(cos^2x+sin^2x) -sin2x/cos2x -tan2x
*May 17, 2016*

**math**

a = -2 r = -2 T20 = ar^19 = 2^20 = (D)
*May 17, 2016*

**Math**

correct
*May 17, 2016*

**Math**

the degree is just the highest power of the variable.
*May 17, 2016*

**Math**

sounds like the prism is 19x6 by 2 so, there are two bases and two pairs of rectangular lateral faces. It's just a box, and you only have to add up the two areas of the rectangles.
*May 17, 2016*

**Calculus**

x+y = 10 p = xy = x(10-x) = 10x-x^2 dp/dx = 10-2x max p at x=5 what a surprise...
*May 17, 2016*

**math**

well, is y/x constant? 40/2 is not 20/5 is xy constant? 2*40 is not 5*20 so, neither direct nor inverse. of course, you could have just tried some values in the various choices to check them...
*May 17, 2016*

**Math**

not sure what tools you have for estimating polynomial roots, but the signs of the quotient from synthetic division tells you that they are all between -2 and 4. Other than that, some numeric method will have to provide better precision.
*May 17, 2016*

**Algebra**

note that each term increases by 5
*May 17, 2016*

**math**

if price is p and cost is c, then normally, p = 1.8c If c increases by 20%, then 1.8c - 1.2c = 0.6c that is, the profit has changed from .8c to .6c, or a decrease of 25%.
*May 17, 2016*

**Math**

7n-3 = 2n+12 7n = 2n+15 5n = 15 n = 3
*May 17, 2016*

**Science**

figure that all the PE has changed to KE
*May 17, 2016*

**math**

for a given perimeter, the largest area is enclosed by a square. That is, all 4 sides are equal...
*May 17, 2016*

**Applied calculus**

you need Fx = 0 and Fy=0 for a max, so -4x^3 + 2y = 0 -4y^3 + 2x = 0 max f=1/2 at x = y = ±1/√2
*May 17, 2016*

**calculus**

z = 1250ln(yx^2)+45(y^2+x)(x^3 -2y)-(xy)^1/2 if x is fixed, dz/dy = 1250/y + 45(2y)(x^3-2y) + 45(y^2+x)(-2) - (1/2)(x)(xy)^(-1/2)
*May 17, 2016*

**calculus**

copy/paste font problems garbled the post
*May 17, 2016*