Tuesday

February 9, 2016
Total # Posts: 37,527

**Pre-Calculus**

enter your coefficients at http://www.mathportal.org/calculators/polynomials-solvers/synthetic-division-calculator.php Looks like you goofed somewhere.
*February 6, 2016*

**Do I have time**

no, but google shows many hits, the first at (wow!) biography.com
*February 6, 2016*

**Do I have time**

Sure you have time. 3 days for 4 more paragraphs? No sweat, if you get to work. Of course, judging by your posting, you have some serious proofreading to do ...
*February 6, 2016*

**algebra 2**

the domain for all polynomials is (-∞,∞) Think about it -- pick any value of x and you can calculate f(x).
*February 6, 2016*

**algebra**

At first I thought your work was a hodgepodge, but further study shows that you are correct. except that 95/7 is not 13. Should have been 91, so you messed up somewhere.
*February 6, 2016*

**Calculus**

No, at 20 mi/hr, every mi/hr increase in speed decreases the fuel consumption by .05 gal/hr. Keep track of the units. Seems kind of odd though, that rate of fuel consumption decreases with increasing speed...
*February 6, 2016*

**Calculus**

#1 ok #2 f' = dc/dv = (gal/hr)/(mi/hr) = gal/mile #3 sort of - see units for #2.
*February 6, 2016*

**Math Radicals**

just expand like normal binomial multiplication: (a+b)^2 (2√5+3)(2√5+3) = (2√5)^2 + 2(2√5)(3) + 3^2 = 4*5 + 12√5 + 9 = 20 + 12√5 + 9
*February 6, 2016*

**math**

p(t) = 4i+8j + (4i+j)t q(t) = 4i+3j + (2i+5j)t the distance pq is d(t) = p(t)-q(t) = 5j + (2i-4j)t = (2t)i + (5-4t)j |d| = √((2t)^2 + (5-4t)^2) = √(20t^2-40t+25) Hmmm. I get √5 as the minimum distance. Better check my math.
*February 6, 2016*

**Mathematics**

8x^3 = 0
*February 6, 2016*

**Math and Physic**

Right off, I'd say the building has zero velocity. as for time to fall, h - 4.9t^2 = 0 plug in t= 7.57
*February 6, 2016*

**Calculus**

If the width is x and the rectangle's height is y, then x+2y + π/2 x = 24 so, y = (24-(1+π/2)x)/2 The area is a = xy + π/2 (x/2)^2 = x(24-(1+π/2)x)/2 + π/8 x^2 = 12x - (1/2 + π/8)x^2 Now just set da/dx=0 to find where the max occurs. Or, use ...
*February 6, 2016*

**sinusoidal functions**

The central axis is at y = 5 y = sin(x)+5 Two consecutive minima are found at (3, −1) and (13, −1) So, the period is 10, the amplitude is 5+1=6, and the shift is 3. cos has max at x=0, but we have a minimum, so y = -6cos(π/5 (x-3))+5 see the graph at http://...
*February 6, 2016*

**math**

rear legs get 2/3 and front get 1/3 now divide those amounts by 2, since there are two front and two rear legs.
*February 6, 2016*

**calc**

f'(p) is the rate of change of quantity as price changes Think of the units: f is yards p is dollars, so df/dp = yards/dollar no idea whether f'(16) is positive or negative. However, it is likely that as price goes up, demand goes down.
*February 6, 2016*

**system of equations**

a + 30b = 1300 a + 80b = 2200
*February 5, 2016*

**Calculus**

looks ok to me y = f^3(g(x)) dy/dx = 3f^2 df/dg * dg/dx for example, y = sin^3(x^2+1) dy/dx = 3sin^2(x^2+1) cos(x^2+1) (2x)
*February 5, 2016*

**Linear Algebra**

depends. what is b? As long as the matrix has a nonzero determinant, there will be a solution.
*February 5, 2016*

**Math**

Looks more like A to me.
*February 5, 2016*

**Geometry**

google online drawing tools. Or, hey! How about this idea? Go Buy Some Graph Paper! Actually, there are online sites which have graph paper you can print.
*February 5, 2016*

**Maths**

review the cotangent function. Draw a diagram and you will see that the distance the plane has flown is 880 cot24°30' - 880 cot67°40'
*February 5, 2016*

**math**

2a+3c = 44.40 3a+6c = 78.00 That's the same as 2a+3c = 44.40 a+2c = 26.00 subtract and you get a+c = 18.40 Note that we don't actually have to find the price of the individual tickets.
*February 5, 2016*

**Geometry**

#1 ok. #2 you figured the length of the hypotenuse. The perimeter is 9+12+15 = 36.
*February 5, 2016*

**math college readiness**

h(t) = 105 - 9t - 16t^2 When does it hit the ground? That would be when h(t) = 0, right? So, just solve the quadratic equation.
*February 5, 2016*

**Math**

If they are linear equations, it is A. Parallel lines (same slope) never intersect. But lines with different slopes must intersect somewhere.
*February 5, 2016*

**Math**

you are correct.
*February 5, 2016*

**math**

If the unknown force is x, then you just need to solve 550 - 300 + x = 0 because the sum of all the forces needs to be zero. I think that once you get your answer you will (a) see why the given formula works (b) notice the typo as written
*February 5, 2016*

**math (sequence and series )**

salary: 1st 8 years: 240 years >= 9: Tn = 9500+360(n-8) Total after 8 years: 8*240 = 1920 n years: (n > 8) Sn = (n-8)/2 (2*9500 + (n-9)*360) So, plug in your numbers for n
*February 5, 2016*

**Physics**

if the graph shows the actual error, just divide that by the correct value. For example if the correct value is 20, and the error is 3, then the percent error is 3/20 = 0.15 = 15%
*February 5, 2016*

**precal**

we can pick any direction for the 1st 3 blocks. Say, North. After the 1st 3 blocks N, E and W are interchangeable. Clearly, going N then S will not help, so she can do one of the following: E for 2, N for 1 E for 2, W for 1 E for 2, S for 1 I think you can tell which gives the...
*February 5, 2016*

**Physics**

well, uh, g, just read off the slope and equate it to 1/2 g: 5.00 = 1/2 g g = 10.00
*February 5, 2016*

**Math**

If each line represents 100 sales, then you are correct.
*February 5, 2016*

**chemistry**

wikipedia has a nice article on calcium, and lists several compounds which are essential for good health. Calcium always forms ionic bonds.
*February 5, 2016*

**Math**

Unless it's a large glass, I'd use ounces. Most glasses are 8-12 oz. Of course, those are fluid ounces. Plain ounces are a measure of weight, not volume. A fluid ounce is the volume occupied by one ounce of water.
*February 5, 2016*

**MATH**

google is your friend. I can tell you how, but you can find many illustrated instructions online. Place compass at one end of line segment. Mark an arc with radius more than half the line length. Do the same at the other end. Make sure the arcs are long enough to intersect in ...
*February 5, 2016*

**Physics**

The basic requirement for destructive interference is that the two waves be shifted by half a wavelength. Now, as you know, v = λν, so just plug in your numbers.
*February 5, 2016*

**Math**

just write that in symbols: nth denominator is 3^(n-1) nth numerator is 3^(n-1) - 2 So, the ntheterm is Tn = (3^(n-1) - 2)/3^(n-1) That can be massaged in various ways: Tn = 1 - 2/3^(n-1) Tn = 1 - 6/3^n Tn = (3^n - 6)/3^n
*February 5, 2016*

**shuluka**

Hora aderat briligi. Nunc et Slythia Tova Plurima gyrabant gymbolitare vabo; Et Borogovorum mimzebant undique formae, Momiferique omnes exgrabure Rathi.
*February 5, 2016*

**Complex number**

recall that (a+bi)(a-bi) = a^2+b^2 (1-i)/(1+i) * (1-i)/(1-i) = (1-i)^2 / (1+1) = (1-2i+i^2)/2 = (1-2i-1)/2 = -2i/2 = -i or, 0 - i
*February 5, 2016*

**Pre-cal**

use Heron's formula, or use law of sines/cosines to determine one of the angles. then the area is 1/2 ab*sinC
*February 5, 2016*

**Maths**

the new length is 4 times the old length.
*February 5, 2016*

**Math**

107.20 * 1.06
*February 5, 2016*

**Math**

if you mean eighteen and fourteen thousandths, that is 18.014
*February 5, 2016*

**calc 1**

The slope at any point is y': y' = 4-6x y'(2) = -8 Now you have a slope and a point: y+4 = -8(x-2)
*February 4, 2016*

**Math**

so, what are the constraints, and the value to maximize? In algebra, not words.
*February 4, 2016*

**calculus**

#1 and #2 look ok (except that x(3) = 18 units, not units/s) #3 flea moving right when x'(t) > 0 (s increasing) #4 evaluate x(t) at the extrema from part 2. Check with this graph: http://www.wolframalpha.com/input/?i=t^3+-+9t^2+%2B+24t #5 x(5)-x(0) #6 ∫[0,5] (1+(x...
*February 4, 2016*

**math**

eh?
*February 4, 2016*

**calc**

#1 as with any parabola, vertex is at t = -b/2a #2 use the t from #1 and evaluate h(t)+6 #3 dh/dt = 64-32t when is that 24 or -24? #4 h(t) = vt-g/2 t^2
*February 4, 2016*

**Math**

if truly linear, the slope is constant. If the slope is close to constant, then the growth is close to linear.
*February 4, 2016*

**algebra - incomplete**

sorry - no table
*February 4, 2016*

**Physics (Electricity)**

E = IR
*February 4, 2016*

**Algebra**

they are the same line, so infinitely many solutions.
*February 4, 2016*

**Algebra**

what, no calculator? Since 2015 is 5 years from 2010, you want to evaluate 32 * 2.1^5 = 1306.9 D should have been clearly wrong, since 2^5=32, so 32*32 = 1024 would be a good guess, though somewhat low.
*February 4, 2016*

**Physics**

recall that the max height is (v sinθ)^2 / (2g)
*February 4, 2016*

**calc 1**

For ε=0.1, you want to find δ such that |f(2+δ)-f(2)| < 0.1 |((2+δ)^3-5(2+δ)+3)-(2^3-5*2+3)| < 0.1 |δ^3+6δ^2+7δ| < 0.1 δ < 0.014
*February 4, 2016*

**MAth**

17 + x <= 26
*February 4, 2016*

**Physics**

would it not be opposite but equal in magnitude? If not so, there would be an acceleration.
*February 4, 2016*

**Physics**

the distance traveled is s = 12.4t - a/2 t^2 = 50.3 The velocity is v = 12.4 - at = 0 Solve that and you get a = 4.59 Now you can use F=ma
*February 4, 2016*

**Physics**

resolve the three forces into x- and y-components. Add them up, and take the magnitude.
*February 4, 2016*

**Algebra 2**

google equation of trend line for lots of help and examples.
*February 4, 2016*

**algebra**

better review your distance formula: d = √((∆x)^2 + (∆y)^2)
*February 4, 2016*

**algebra**

since the midpoint is halfway between the ends, its coordinates are the average of the x and y of the ends.
*February 4, 2016*

**algebra**

the perpendicular line has slope -4 Now you have a point and a slope, so use the point-slope form of the line. Then rearrange to slope-intercept form.
*February 4, 2016*

**algebra**

to find the x-intercept, set y=0 for the y-intercept, set x=0 Now you have two points on the axes -- connect them with a line.
*February 4, 2016*

**algebra**

why all those cluttery words? This is math, not English. x^2+y^2+8x-8y-49 = 0 x^2+8x + y^2-8y = 49 Now complete the squares: x^2+8x+16 + y^2-8y+16 = 49+16+16 (x+4)^2 + (y-4)^2 = 81 I think you can prolly take it from there, eh?
*February 4, 2016*

**Algebra**

it helps if you can find the roots of the function. In this case, you have y=(x+1)(x^2+16) So, you know the graph crosses the x-axis only at x = -1. Since the 2nd factor is always positive, y>0 where (x+1) > 0. Think you can take it from there?
*February 4, 2016*

**anty alice**

type you equation in at wolframalpha.com
*February 4, 2016*

**math**

Draw a diagram. The slant height is s = 42/cos30°
*February 4, 2016*

**maths**

check the intercepts. when x=0, y=b when y=0, x=a so, you have a right triangle with legs a and b, so its area is ab/2
*February 4, 2016*

**Calculus**

If the angle is x, then you have a trapezoid with lower base 4", and upper base 4+2*4cosx, and height 4sinx. So, the area of the cross-section is a = (4 + (4+8cosx))/2 * (4sinx) = 16 sinx (1+cosx) da/dx = 16(2cos^2(x)+cos(x)-1) = 16(2cosx-1)(cosx+1) da/dx=0 when cosx = 1/...
*February 4, 2016*

**circumference...math**

recall that the circumference of a circle of diameter d is C = πd
*February 4, 2016*

**Math**

vertical angles are equal, so 7x+7=112 x=15 you are correct.
*February 4, 2016*

**math**

solve for t with e^(.10*t) = 2
*February 4, 2016*

**math**

the small gear turns 4 times as fast as the large one.
*February 3, 2016*

**Math**

looks ok to me.
*February 3, 2016*

**maths**

well, here's the graph: http://www.wolframalpha.com/input/?i=%282^x%29%28cot+x%29%2Fx^1%2F2 did you have some question about it?
*February 3, 2016*

**MATH**

well, a = 8 r = 3/4 Tn = 8 * (3/4)^(n-1)
*February 3, 2016*

**Calculus**

what is the height of the tank? You need to know how far above the top of the oil is the spout, and how deep is the oil. Anyway, assuming the oil has a depth of d meters, and the spout is h meters above the top of the oil, then consider the oil as a stack of thin slices of ...
*February 3, 2016*

**Calculus**

a = dv/dt, so v(t) = 2t^3 = 2*6^3
*February 3, 2016*

**Calculus**

all look ok to me. good work.
*February 3, 2016*

**calculus 1**

clearly the limit is (8+1)/(6-4) = 9/2 Not sure what your definition 2 is, but if you need to find δ such that |f(x+δ)-9/2| < 0.5 then that means |(4(2+δ)+1)/(3(2+δ)-4)-9/2| < 0.5 Work your way through that and you will find that δ < 0.125 So...
*February 3, 2016*

**Math **

(a) stretch by 2 and shift up 3 (b) shift left 1 and down 3 (c) shrink by 2 and reflect in x-axis (d) shift left 1, reflect in y-axis, reflect in x-axis, shift up 3. Just plug in your numbers to find the image of the point.
*February 3, 2016*

**Geometry**

22+16-32 = 6 So, there are 6 juniors who do both. P(both) = 6/50 = 3/25
*February 3, 2016*

**Math**

assuming you have a hemisphere atop a cylinder, they both have the same radius. So, just plug your numbers into the usual volume formulas.
*February 3, 2016*

**Math**

clearly y is discontinuous at x=0, since lim(x->0-) = 3 lim(x->0+) = 1 y'=-2x for x<0 y'=2x for x>0 y" = -2 for x<0 y" = +2 for x>0 so, y is increasing everywhere, since y'>0 everywhere it is defined. y is concave down for x<0 y is...
*February 3, 2016*

**Writing equations to represent situations**

x = 17 xy = 680 2(x+y) = ?
*February 3, 2016*

**Math**

1: probably a trapezoid 2: Must mean that there are two such congruent sides, not that all pairs are congruent. Might be a trapezoid or a kite. 3: could be a rectangle or trapezoid. Diagonals of a rhombus are not equal. 4: general quadrilateral. Try drawing one 5: kite Try ...
*February 3, 2016*

**Math**

well, there are 57/y bananas That means there must be only 57/y apples, so the result will be 57/y oranges, each having mass x+y so, the mass of oranges will be 57(x+y)/y = 57(1+x/y) grams
*February 3, 2016*

**Math**

as always, swap variables and solve for y: 3x+5y=18 5y = 18-3x y = (18-3x)/5 Did the other one in your previous post (see related questions below)
*February 3, 2016*

**Math**

I think you are missing something. Each added triangle has a smaller area and a smaller perimeter. I think I am missing something, too. If all the triangles are inscribed into the same area, the total area is unchanged, right? By "the perimeter" do you mean the sum ...
*February 3, 2016*

**physics**

log1519
*February 3, 2016*

**math**

y = 144+(115.2-144)/(14) x = 144-2.057x Now just plug in values for x.
*February 3, 2016*

**Algebra**

(6x^-2)^2 = 36 x^-4 (1/2 x)^4 = 1/16 x^4 multiply and you get 36/36 = 9/4 = 2.25 If you want us to analyze your work, you need to show it!
*February 3, 2016*

**algebra**

if there are all positive exponents, then it is a polynomial. Terms are separated by +/- signs, so just count the terms to determine the type. Add the exponents in each term; the highest sum is the degree of the polynomial.
*February 3, 2016*

**science/maths**

divide those time values by 60, since they are in minutes, not hours.
*February 3, 2016*

**Algebra**

If the slow plane's speed is x mi/hr, then since distance=speed*time, 4x + 4(x+65) = 2660
*February 3, 2016*

**Algebra**

f◦g = f(g) = 3/(g-3) = 3/((2/x)-3) = 3/((2-3x)/x) = (3x)/(2-3x) It looks like the domain of f◦g is all reals except x=2/3, but we also have to exclude x=0, since g is not defined there.
*February 3, 2016*

**math**

it is just the product of the two primes, since there are no common factors.
*February 3, 2016*

**maths**

review the definition of cot(x). Draw a diagram and you can see that h*cot45 - h*cot60 = 100
*February 3, 2016*

**math**

Take a look at this site to see a very similar problem: https://www.quora.com/If-2f-x-3f-left-frac-1-x-right-+-x-2-then-f-2
*February 3, 2016*