Thursday

November 26, 2015
Total # Posts: 35,796

**Vector resultant angles**

well, its angle θ is tanθ = 12/-9 did you actually try drawing a diagram? I assume you can convert from the conventional trig angles to compass directions ...
*October 21, 2015*

**Algebra**

clearly the smaller wheel has 2/3 the diameter of the larger wheel. So, it has 2/3 * 18 = 12 teeth. So, what is 7/12 of its circumference?
*October 21, 2015*

**Math**

40 is not the answer. She wants to read at least 200 pages, so she needs to read at least 40 pages per day: p >= 40
*October 21, 2015*

**Math**

5p >= 200 p >= 40
*October 21, 2015*

**Algebra I**

This is the formula for compound interest on a fixed deposit. It is not the formula for loan amortization, which takes into account the declining balance. Better check you formula list. However, if that's the formula you were supposed to use, you did it right.
*October 21, 2015*

**math**

If the original width is w, then the length is 2w-3. After the changes, 2((2w+3)-2 + w-1) 24
*October 21, 2015*

**ai**

240/3.5 mi/hr
*October 21, 2015*

**math**

there's no equation. You just want to factor out a common value (3) to illustrate the distributive property. 3w+18 = 3*w + 3*6 = 3(w+6)
*October 21, 2015*

**Geometry**

If the interior angles are x and y, x+y=90 (180-x)/(180-y) = 13/14 Now find x and y and pick the smaller.
*October 21, 2015*

**math**

x = 150/3
*October 21, 2015*

**Math**

looks good to me. but why did you not just write 30.3/10 ?
*October 21, 2015*

**features stars**

A∪B = {1,3,5,7,9}∪{1,2,3,4,5,6} = {1,2,3,4,5,6,7,9}
*October 21, 2015*

**Trigonometry**

as always, draw a diagram. Since the front is 5' taller than the back, the angle you want is θ, such that tanθ = 5/11
*October 21, 2015*

**trig**

a complete turn of the hoist is π ft a complete turn is 360° So, the hoist turns through (2.6/π) * 360°
*October 21, 2015*

**Trig**

The angular speed is (2π / 7.6896*10^6) rad/s
*October 21, 2015*

**Trig**

as always, draw a diagram. You can easily see that the length w is (190-30)/w = sin 39°
*October 21, 2015*

**Calculus i need help plz plz**

∫(sinx cosx)/(a^2 cos^2(x) + b^2 sin^2(x)) dx well, let's see. a^2 cos^2(x) + b^2 sin^2(x) = a^2 cos^2(x) + a^2 sin^2(x) + (b^2-a^2)sin^2(x) = a^2 + (b^2-a^2) sin^2(x) so, if u = a^2 + (b^2-a^2) sin^2(x) du = 2(b^2-a^2) sinx cosx dx and your integral now becomes 1/2...
*October 21, 2015*

**math**

start with x spend 2 on magazine, leaving x-2 spend (x-2)/2 on shoes, leaving (x-2)/2 spend ((x-2)/2)/2 leaving (x-2)/4 (x-2)/4 = 12 x = 50 check: start with 50 spend 2, leaving 48 spend half, leaving 24 spend half, leaving 12
*October 21, 2015*

**algebra 2**

so, what is confusing about using the quadratic formula? h^2 + 5h - 295 = 0 h = (-5±√(5^2 + 4*295)]/2 not so bad, eh?
*October 21, 2015*

**Math**

1+i^4 = 1+4i+6i^2+4i^3+i^4 = 1+4i-6-4i+1 = -4 or, 1+i = √2 cis 3π/4 so, (1+i)^4 = 4 cis3π = -4 I guess you can take it from there, right?
*October 21, 2015*

**math**

If x is at 6%, then the rest (12600-x) is at 8%. So, add up the interest: .06x + .08(12600-x) = 864.00
*October 21, 2015*

**maths**

25yd/30s = 5/6 yd/s
*October 21, 2015*

**algebra**

inner area: 100*50 outer area: (100+2*2)(50+2*2) border area = (outer area) - (inner area)
*October 21, 2015*

**Math**

I see you fixed the numbers. Can you not follow the method I showed you? Where do you get stuck? See related questions below
*October 21, 2015*

**Math**

If the fixed cost is x, and the repeated cost is y per card, then x+30y=800 x+550y=1300 clearly 520y = 500 Now you know y, and you can find x, and then x+1000y I suspect a typo, and you must have meant 300 cards or 330 cards or something. Still, follow the steps. as for Amanda...
*October 21, 2015*

**Math PLZZ**

#1 is ok #2 ??How can the hypotenuse be shorter than either leg? #3 bzzt 2^2+5^2 = 4+25 = 29, not 36 #4 the hypotenuse is 20√2. √2 ≈ 1.4, so not 30, which is 20*1.5
*October 21, 2015*

**h**

m+s = 40 m+10 = 2(s+10)
*October 21, 2015*

**math**

x+y=120 3x = 2y
*October 21, 2015*

**Maths ( urgent help )**

in 6 days, the 20 men have done 1/4 of the work. One man can do 1/480 of the work in a day. So, if x men finish 3/4 of the work in 15 more days, that means x/480 * 15 = 3/4 x = 24 So, 4 extra men were hired.
*October 21, 2015*

**Calculus 1**

f = 4cosθ + 2sin^2θ = 4cosθ + 2 - 2cos^2θ f' = -4sinθ + 4cosθsinθ critical numbers are when f'=0, so 4sinθ(cosθ-1) = 0 so, sinθ=0 or cosθ=1 ...
*October 21, 2015*

**Calculus 1**

It would sure be nice if you showed that you are willing to provide at least a little input on these. Just sayin' f = x^5 e^(-6x) f' = x^4 e^(-6x) (5-6x) so, where is f'=0? Hint: e^(-6x) is never zero.
*October 21, 2015*

**Calculus 1**

f' = 2x^3(x-2) / 5(x-1)^3 you want f'=0
*October 21, 2015*

**Calculus 1**

h' = 3/4 t^-1/4 - 3/4 t^-3/4 = 3/4 t^-3/4 (t^1/2 - 1) so, when is h' = 0?
*October 21, 2015*

**Algebra**

3*83 <= 80+86+x <= 3*88 Now just isolate x in the middle.
*October 21, 2015*

**Math**

3^2 x 5^-3 x 2 = 2*3^2/5^3 2^-8 x 3^5 = 3^5/2^8 dividing (multiplying by the reciprocal) we have 2*3^2/5^3 * 2^8/3^5 = 2^9 / (5^3 * 3^3) = 2^9 / 15^3 = 8^3/15^3 = (8/15)^3
*October 20, 2015*

**Math**

(2x^3y)^6 = 2^6 (x^3)^6 y^6 = 64x^18y^6 Now multiply that by 3x and you have 192x^19y^6
*October 20, 2015*

**Math**

3 2/5 = 17/5 (17/5 mi)/(5/6 hr) = 102/25 mi/hr
*October 20, 2015*

**Calculus**

df = 10t dt so, df = 10(4)(0.01) = 0.4
*October 20, 2015*

**Math Pre-Algebra**

(9s-4)/9 (-2/3) = -4/5 -2(9s-4)/27 = -4/5 Multiply both sides by 27*5 and you have -2(5)(9s-4) = -4*27 -90s+40 = -108 and so on...
*October 20, 2015*

**Math 142 (calculus)**

just use the chain rule y' = 4(5x^5+7)^3 (25x^4) = 100x^4 (5x^5+7)^3 Now again, also using the product rule y" = 400x^3 (5x+7)^3 + 100x^4 * 3(5x^5+7)^2 (25x) = 100x^3 (5x^5+7)^2 (95x^5+28)
*October 20, 2015*

**ALGEBRA**

g(x) = f(x+5)+8
*October 20, 2015*

**Pre-algebra**

first, expand the parentheses to get -2t-16 = 12 Now go for it.
*October 20, 2015*

**Math**

well, one thing you could do is multiply correctly: n(n-1)(n-2) = n^3 - 3n^2 + 2n so, n^3 - 3n^2 + 2n = 120 n^3 - 3n^2 + 2n - 120 = 0 That could be hard, but try some integer roots. A little synthetic division yields n^3 - 3n^2 + 2n - 120 = (n-6)(n^2+3n+20)
*October 20, 2015*

**math**

since the ratio r is common, (2k-1)/(k+1) = (3k+1)/(2k-1) k=0 or 8 Now you can find r.
*October 20, 2015*

**Math**

ummm how about 678*6 700*6 = 4200 600*6 = 3600 So, I'd say about 4000
*October 20, 2015*

**Counting and Probability**

2-digits, can't be hard 9 numbers ending in 1 10 numbers beginning with 1 11 occurs in both lists.
*October 20, 2015*

**maths**

since time = distance/speed, 34/(x + 1/2) = 34/x - 1/2
*October 20, 2015*

**maths**

1/(x-40) + 1/x = 1/48
*October 20, 2015*

**@John**

You got your speeds reversed, John. The slower speed takes longer.
*October 20, 2015*

**maths**

since time = distance/speed, 100/(50-x) = 100/(50+x) + 3.75 Now just find x.
*October 20, 2015*

**MATH**

these were all done by Bosnian earlier. Look for them and stop reposting.
*October 20, 2015*

**Math**

the total is divided into 5 parts + 7 parts, making 5+7=12 parts in all. So, won/all = 7/12
*October 20, 2015*

**Math**

draw the triangle In the triangle, label the sides 1 and u, and the hypotenuse √(1+u^2) the angle tan^-1(u) is opposite the "u" side, since opposite/adjacent = u/1 = u So, the cosine of that angle is adjacent/hypotenuse = 1/√(1+u^2) You can also note that...
*October 20, 2015*

**Calculus**

y = ax^b/lnx y' = (ax^(b-1) (b*logx - 1))/log^2(x) since x^b is never zero, we want b logx = 1 b = 1/ln(1/5) = -0.62133 y = ax^b/lnx y(1/5) = 1, so a (1/5)^(-0.62133)/-ln5 = 1 a = -ln5/((1/5)^(-0.62133)) -0.59208 y = -0.59208 x^-0.62133 / lnx check at http://www....
*October 20, 2015*

**Math**

a full tank is 4/3 as much as a 3/4 tank. So, 4/3 * 14.5
*October 20, 2015*

**math - eh?**

number increased by 10: x+10 5 times a number increased by 10: 5(x+10) 3 less than 5 times a number increased by 10: 5(x+10)-3 Now you have "the sum of" all that ... and what? sum of needs two values. I think the question is bungled.
*October 20, 2015*

**algebra,**

well, just plug in 6.3 for a: 2(6.3)+b = 15.7 Now just solve for b.
*October 20, 2015*

**MaTh**

How about I do a few and you show where you get stuck? -5g - 6 for g= -2 just plug in -2 for any g's: -5(-2)-6 = 10-6 = 4 when you see sum, it means add. So, sum of 3 and c is 3+c or c+3 20b-16 4(5b-4) You must surely have some ideas on the rest. If not, you are in big ...
*October 20, 2015*

**spelling**

google is your friend. Use it and you will get many many examples.
*October 20, 2015*

**MATH**

I pick D B is (-1/3) ÷ (1/2)
*October 20, 2015*

**Algebra**

looks good to me.
*October 20, 2015*

**Algebra 2**

so, how many ways are there to pick the two even throws from 6 throws?
*October 20, 2015*

**Algebra 2**

P(even) = 1/2 s, P(even,even) = 1/2 * 1/2 = 1/4
*October 20, 2015*

**Pre-calculus**

no matter. the proposed answer is bogus. The directrix is a line, not just a number. Recall that the parabola y^2 = 4px has directrix at x = -p. Your parabola is shifted up, but that does not change the directrix. So, the desired line is clearly x = -3 see the properties at ...
*October 20, 2015*

**algebra**

Train A went for 2 hours before B started. B, going 20 mph faster took 5 hours to catch up. So A was 100 miles ahead. That means A went 100 miles in 2 hours. I think you can take it from here, no?
*October 20, 2015*

**Maths plz help**

so that leaves 4 questions from 6, or 6C4 = 6C2 = 15
*October 20, 2015*

**algebra**

T(p+q) = ar^(p+q-1) = m T(p-q) = ar^(p-q-1) = n multiplying, r^(2p-2) = mn dividing, r^(2q) = m/n you should be able to use that to find T(p) and T(q)
*October 20, 2015*

**Math**

get some graph paper, with small squares on it. Plot two points and draw a line between them. The points come from your table. google will provide lots of examples. As will your textbook, no doubt...
*October 20, 2015*

**Math Help!**

1.2^2 = 1.44 1.7^2 = 2.89 2^2 = 4 So, C looks good. 81 = 9^2 100 = 10^2 93 is kind of in the middle, so what is midway between 9 and 10?
*October 20, 2015*

**Math Help!**

correct.
*October 20, 2015*

**Math Help!**

If you mean -√66, just think a minute: √36 = 6 √49 = 7 √64 = 8 √81 = 9 66 is close to 64, so √66 is close to 8 But, you have -√66, so C looks good to me.
*October 20, 2015*

**Math**

well, just divide the cost by the weight: ($10.00)/(2 2/3 lb) = ($10.00)/(8/3 lb) = $3.75/lb
*October 20, 2015*

**Algebra 1 HELP PLEASE!**

V is a set, just as P is a set. The question is, what does P◦V mean? I haven't seen that notation used. If it supposed to be the intersection (usually written P∩V), then it wold be the set of elements in both P and V: P∩V = {2,4,6,8} So, figure out what P...
*October 20, 2015*

**Algebra**

1/48 + 1/144 = 1/x
*October 20, 2015*

**Math**

69 + 3*23, so multiply each number in the proportion by 23: 3:5:2 = 69:115:46 Now you know how many there are in each group.
*October 20, 2015*

**Calculus...need help**

You can read through this http://mathhelpforum.com/calculus/230533-integral-1-x-sqrt-ax-2-b-x-c-dx.html or recall that arcsinh(u) = log(u + √(u^2+1)) and see where that takes you.
*October 20, 2015*

**Algebra plz help**

both correct.
*October 20, 2015*

**algebra**

a+2d = 8 a+8d = 3(a+2d)+2 = 26 so, 6d = 18, and d=3 Now you can find a, and answer the question.
*October 20, 2015*

**math**

If I gave you 5 hot dogs and you ate one every hour, how long would they last? This is exactly the same problem, but with different numbers. Think about how you'd solve the question I gave you, and follow the same steps for your own problem.
*October 20, 2015*

**Calculus 1**

excuse me? You don't know where the maxima and minima are on cos(x)? Don't forget your trig now that you're doing calculus. If nothing else, just find f' and see where it's zero. Is there some trick to this question beyond what you have posted?
*October 20, 2015*

**math**

Not sure what the temperature is, but the altitude will be 1800-60*15 meters.
*October 20, 2015*

**math**

anything that decreases by 100% ends up at zero.
*October 20, 2015*

**Math**

w(2w)=8
*October 20, 2015*

**Calculus 1**

that's the problem with complicated stuff like this. There are always several ways to write it. Bad area for short-answer responses.
*October 20, 2015*

**Calculus 1**

It looks good, but could probably be massaged a bit. How about (2-6logx)/x^4
*October 20, 2015*

**Physics 101 (I'm stupid)!**

mass never changes. Only the weight does. The weight is mg, on whatever planet is doing the gravity.
*October 20, 2015*

**PHYSICS**

well, 60 km/hr = 16.67 m/s v(t) = 16.67 - 5.6t set v=0 and solve for t, then plug that into s(t) = 16.67t - 2.8t^2
*October 19, 2015*

**Math**

maximum volume is where the derivative is zero. 12x^2-56x+33 = 0 so, just use the quadratic formula to find where that is.
*October 19, 2015*

**Geometry**

It appears that the 3rd side is y, so yes, that means y + (y+10) + (y^2-2) = 21 y^2+2y+8 = 21 y^2+2y-13 = 0 now use the quadratic formula. If you want an integer or rational answer, there must be a typo somewhere.
*October 19, 2015*

**Simple interest math**

.053n = 1
*October 19, 2015*

**Science**

well, it increased by 40 km/hr in 9 s, so the acceleration is 40/9 km/(hr-s) Not the usual units, so let's make everything meters and seconds 40/9 km/hr-s * 1000m/km * 1hr/3600s = 1.234 m/s^2
*October 19, 2015*

**Algebra**

well, 8a+8b = 8(a+b)
*October 19, 2015*

**Math**

Nope (C) Do not change the direction of the inequality unless you multiply by a negative number.
*October 19, 2015*

**math**

x(20-x) = 0
*October 19, 2015*

**math**

√12 x √30 -√20 x √8 √360 - √160 √(36*10) - √(16*10) (6-4)√10 2√10
*October 19, 2015*

**algebra**

see related questions below.
*October 19, 2015*

**Steve look i have corrrected it help plz it urgent anyone plz**

Maybe you should consult someone local who can understand your garbled instructions. Like, oh, I don't know, someone who speaks your language?
*October 19, 2015*

**math**

since there is no question here, I have no idea how the answer was achieved, nor what it might mean.
*October 19, 2015*

**Algebra word problem.....so difficult**

Where do you get this stuff? No way the problem was presented in those words! I'll assume that "last three year" means "three years ago". "next nine years" means "nine years from now" We have three ages: m: me k: kemi f: femi We are ...
*October 19, 2015*