Sunday

February 7, 2016
Total # Posts: 37,440

**math**

geez, give it a rest already, willya? 10^3 * 26^2
*January 28, 2016*

**geometry**

clearly, when the longest side is the sum of the other two sides, the triangle has flattened into a line. So, 17-x = 8-x + 15-x 17-x = 23-2x x = 6 cutting off 6" leaves the lengths of 2,9,11, a flat triangle.
*January 28, 2016*

**Math**

Starting with $10, I bought 3 candy bars at 75 cents each, and 2 sodas at 50 cents each. How much money was left after the purchases?
*January 28, 2016*

**Math**

p=3s s=2m p-(x+y) = s+x p-(x+y) = m+y If p gives away 1/2 of his eggs, 1/6 to s and 1/3 to m, then Pablo has p/2 Sofia has p/3 + p/6 = p/2 Mia has p/6 + p/3 = p/2
*January 28, 2016*

**Math Help**

well, we are told that v(t) is the velocity at time t. Looks like B to me.
*January 28, 2016*

**Help Math**

exatamente correto de nada
*January 28, 2016*

**math**

37/1 -16/5 92/10 = 46/5 -23/100
*January 28, 2016*

**Algebra**

If there were x of each to start, then x = 4(x-66)
*January 28, 2016*

**writing equations-Math**

20(x-2) = 60 60/(x-2) = 20
*January 28, 2016*

**triggggg help**

well, tan = sin/cos, right? Also, 67.5° = 3pi/8 = tan(1/2 * 3pi/4) so you can use the half-angle formula tan(x/2) = sinx/(1+cosx) tan 3pi/8 = (1/√2)/(1-1/√2) = (1/√2) / (√2-1)/√2 = 1/(√2-1) = √2+1 or, √((2+√2)/(2-√...
*January 28, 2016*

**Calculus**

(√(6-x)-2)/(√(10-x)-3) (√(6-x)-2)(√(10-x)+3) ----------------------- (√(10-x)-3)(√(10-x)+3) (√(6-x)-2)(√(10-x)+3) ---------------------- 10-x-9 as x->1, that is (6√5 - 12)/±0 undefined
*January 28, 2016*

**Tips**

Once you have submitted your question, the screen will show a line like Your question, Tips, was successfully posted Click on the word Tips and your posting will open up again for your review. Proofread it and watch for typos, formatting, font problems, etc. Make sure it is ...
*January 28, 2016*

**Tips**

See tips below.
*January 28, 2016*

**Calculus**

http://www.jiskha.com/display.cgi?id=1453991598
*January 28, 2016*

**Math**

1/2 = 2^-1 32 = 2^5, so (2^-1)^(2-x) = (2^5)^(x+1) 2^(-1(2-x)) = 2^(5(x+1)) -2+x = 5x+5 4x = -7 x = -7/4
*January 28, 2016*

**intermediate algebra**

since time = distance/speed, 186/(24+x) = 102/(24-x)
*January 28, 2016*

**Math**

Draw a diagram. The line from the satellite and a city is tangent to the radius from the center of the earth. If that radius is r, then the angle θ subtended by the satellite and one city is θ = 1125/r So, if the satellite is h mi high, r/(r+h) = cosθ h = r/cos...
*January 28, 2016*

**Math**

sorry - ain't so. Check for typos However, cot(sec^-1(A)) = √(A^2-1) cot^2(sec^-1(A)) = A^2-1 I think I can see how the question was mangled. Can you?
*January 28, 2016*

**math**

take a look at the 2nd related question below.
*January 28, 2016*

**Calculus**

since p(t) is the population given time, p^-1(t) is the time needed to attain a certain population. p=7500/(1+749e^-0.15t) 1+749e^-0.15t = 7500/p 749e^-0.15t = 7500/p - 1 e^-0.15t = (7500/p - 1)/749 -0.15t = ln((7500/p - 1)/749) t = -20/3 ln((7500/p - 1)/749) or t = -20/3 ln((...
*January 28, 2016*

**maths**

(1) 1600*30 (2) 0 (3) p = mv, so dp/dt = m dv/dt = 1600*(0-30)/(20-0) = -2400 kg-m/s (4) see (3) (5) F = ma
*January 28, 2016*

**math**

start here, where the facts are written as algebra: x+y = 120 3x = 2y
*January 28, 2016*

**mathematics**

there are many good amortization calculators online.
*January 28, 2016*

**analytic geometry**

see related questions below
*January 28, 2016*

**math**

c = 5b c+2 = 3(b+2) c+2 = 3(c/5 + 2) c+2 = 3c/5 + 6 2c/5 = 4 c = 4*5/2 c = 10 Check: Carol is now 10, brother is 2 in two years, Carol is 12, brother is 4
*January 28, 2016*

**math**

Kleeneces
*January 28, 2016*

**Math**

No idea about Jean, but (3/5)/(1/9) = 27/5 or 5 2/5 as much
*January 28, 2016*

**maths**

well, start with s = rθ and then plug in your numbers θ is in radians, not degrees.
*January 28, 2016*

**maths**

since 8 mo. is 2/3 year, 2520(2/3)(r/100) = 84
*January 28, 2016*

**Maths**

since time = distance/speed, 40/x + 250/(x+20) = 3
*January 28, 2016*

**calc**

I think you must mean s(t) = e^(cos(t)) velocity is zero when v(t) = ds/dt = e^cos(t) (-sin(t)) = 0 sin(t)=0 when t is a multiple of pi. So, it looks like you are in error.
*January 28, 2016*

**Math**

I don't think you can answer the question without knowing how much the mirror had to be tilted. If the mirror is tilted an angle x, and the angle θ from the normal is formed by the ray from eye to mirror to window, then we have (if the height of the window is h): 1.82...
*January 28, 2016*

**analytic geometry**

the asymptotes are always y=±(b/a)x 2x^2 + 5y^2 - 16x + 20y + 108 =0 2x^2-16x + 5y^2+20y + 108 = 0 2(x^2-8x) + 5(y^2+4y) + 108 = 0 2(x^2-8x+16) + 5(y^2+4y+4) + 108 - 2(16) - 5(4) 2(x-4)^2 + 5(y+2)^2 + 56 = 0 I suspect a typo, since the above equation has no real ...
*January 28, 2016*

**Math**

you can multiply the 2nd equation by -5, and then you have 5x + 2y = 1 -5x + 15y = -35 Now you can easily add them to get rid of x, then find y.
*January 28, 2016*

**Calc II**

4sec(x) dy/dx = e^(y+sin(x)) 4secx dy = e^y e^sinx dx e^-y dy = 1/4 e^sinx cosx dx -e^-y = 1/4 e^sinx + c e^-y = -1/4 e^sinx + c -y = ln(c - e^sinx/4) y = -ln(c - e^sinx/4) y(0) = -5, so -5 = -ln(c - 1/4) 5 = ln(c - 1/4) e^5 = c - 1/4 c = 1/4 + e^5 y = -ln(1/4 + e^5 - e^sinx/4)
*January 28, 2016*

**analytic geometry**

y^2 = 4px has directrix x = -p focus x = p the l.r. has length 2p. No electricity is involved. the l.r. of an ellipse has length 2b^2/a recall that b^2+c^2 = a^2 and eccentricity is c/a
*January 28, 2016*

**math**

just set R(x) = C(x) and solve for x.
*January 28, 2016*

**Math**

well, you know y=10-6x so substitute that into the other equation.
*January 28, 2016*

**operating system**

LRU
*January 28, 2016*

**Math**

only two
*January 27, 2016*

**analytic geometry**

However, they wanted the acute angle. So, Sylvia, now it's up to you...
*January 27, 2016*

**Math**

(1/4 + 2/3)x + 200 = x
*January 27, 2016*

**Riddle**

man's mother's nephew is a cousin of the man cousins have the same grandparents. so, the woman's father is also the man's cousin. 2nd cousins share the same great-grandparents. So, the man and the woman are 2nd cousins, once removed.
*January 27, 2016*

**AAMU**

speed = distance/time, so (2+2)/(2/8 + 2/6) = 48/7 km/h
*January 27, 2016*

**Math**

what is the only symbol which has no definite value?
*January 27, 2016*

**math**

If you worked x hours, then sister worked 7-x hours. So, now you just have to solve 4x + 5(7-x) = 32 Plug and chug.
*January 27, 2016*

**Math**

5/3 g + 5/6 - g = 2/3 g + 5/6 or (4g+5)/6
*January 27, 2016*

**Pre-calculus**

We have a right triangle whose hypotenuse is the distance (d) between the boats: d^2 = 16t^2 + 18(t-1)^2
*January 27, 2016*

**Pre-calculus**

assuming the tank is pointed-end down, the water forms a cone, so v = π/3 r^2 h Now, using similar triangles, (r/h) = 9/16, so v = (π/3)(9/16 h)^2 h = 27π/256 h^3 h = 3/8 ∛(2πv) since this is precal, not calculus, I'm not sure what tools you have ...
*January 27, 2016*

**Math**

you are correct.
*January 27, 2016*

**math**

just add the differences to the average. Clearly the results will be in the same order as the differences.
*January 27, 2016*

**math...finding cubic feet**

well, v = πr^2 h so, plug in your numbers. Apparently the radius is 3/8 inches Then recall that it takes 1278 in^3 to make 1 ft^3.
*January 27, 2016*

**Calc 1 limits**

If you canceled out the x+3 terms, that leaves the x-3 terms, so your quotient is 1/(x-3)^2 But your answer is indeed 1/36
*January 27, 2016*

**trigonometry**

use the difference formula: sin(π-x) = sinπ cosx - cosπ sinx sinπ=0 and cosπ = -1, so you wind up with 0 - (-1)(sinx) = sinx Also, if you draw the angles in standard position, recall that sinθ = y/r cosθ = x/r since y is positive in QI and ...
*January 26, 2016*

**Math**

for the cone, the slant height s and the height h and the radius r obey s^2 = r^2+h^2 so, the height is √20=2√5 cone volume is 1/3 πr^2h = 32√5 π/3 cylinder volume is πr^2h = 102π so add them up
*January 26, 2016*

**Math**

the area of the base with diameter d is π/4 d^2 = π/4 * .5^2 = π/16 the volume is just base * height better review your formulas. Here's a good reference: http://www.regentsprep.org/regents/math/algebra/as2/solids.htm if you still have questions, or just ...
*January 26, 2016*

**Math**

no problem. Of course, telling me the front side has the line does not help, since I cannot see which face is the front.
*January 26, 2016*

**Math**

just plug the numbers into your volume formulas. The square-ish part cannot be a cube, since the sides differ in length. Must be a rectangular prism. You don't say which side has the diagonal line, but using the Pythagorean theorem to find h, if it is on the 1" side, ...
*January 26, 2016*

**Calculus**

Just keep in mind the chain rule. Every time you have a y, you will produce a y'. x^2 = (x-y)/(x+y) 2x = ((1-y')(x+y) - (x-y)(1+y'))/(x+y)^2 At this point, it's just algebra. Collect all the y' stuff on one side, and you wind up with (one form, anyway): y&#...
*January 26, 2016*

**input output**

Look at the first two terms. x increases by 8, and y increases by 12. So, clearly the rule is y=(3/2)x + ... Since (3/2)*4=6, and y=6, our rule must be just the above: y = 3/2 x So, when y=60, x=40 Fill in the blank with any convenient values: 20, 30 comes to mind.
*January 26, 2016*

**Math**

If the length is x, then 2(90+x) = 500
*January 26, 2016*

**6th Grade Math**

Note that (3/4)(4/3) = 1 That is, 1 hour is 4/3 as long as 3/4 hour. So, he can mow 4/3 as much: (2/3)(4/3) = 8/9 of the lawn.
*January 26, 2016*

**perimeter and area**

correct on both.
*January 26, 2016*

**Science**

use a third container. Pour lemonade from one glass into it and mark its height. Then do the same with the other glass. If the height is the same, the glasses contain the same volume of drink.
*January 26, 2016*

**Algebra 1**

#1 growth factor: 1.22 initial: 180 at 8pm: 180 * 1.22^8 Consider how I derived the math from the words, and work on the others. Let us know which items seem difficult.
*January 26, 2016*

**Math**

to what? clarify your question if you want a helpful answer.
*January 26, 2016*

**math**

try using a common denominator: 3/10, 4/10, ... , 6/10, 7/10 now it's easy, right? Tn = (n+2)/10
*January 26, 2016*

**math**

given only two terms, it is possible to make up a variety of ways to get from one to the other. However, since the two values are 3/10, 4/10 The easiest rule I can think of is just to add 1/10 to get the next term.
*January 26, 2016*

**selma high**

42
*January 26, 2016*

**MATH HELP**

the radius of the cone is the same as the radius of the cylinder. Then if you have the heights of the cylinder and cone, just use the normal volume formulas.
*January 26, 2016*

**MATH**

no. did you check to see that your answer works? q^2 = 4 since 32q^2 = 8*4*4 = 32*4
*January 26, 2016*

**MATH**

pq^2=k so, you want q such that 32q^2 = 8*4^2
*January 26, 2016*

**math**

forget the p. It is just a scale factor. using the law of cosines, 6^2 = 4^2 + 5^2 - 2*4*5*cosA A = 82.82° Now do a similar equation for B, and then C is easy, since A+B+C=180
*January 26, 2016*

**math**

since Lucy pays 30%, her share will increase by .30(650-450)
*January 26, 2016*

**math**

450 * 4π cm
*January 26, 2016*

**Math**

g^-1(x) = 16-4x f^-1(x) = x/4 - 1/16 (g∘f)^-1 = 63/16 - x (f^-1 ∘ g^-1)(x) = (16-4x)/4-1 = 63/16 - x It is not hard to show that (g∘f)^-1(x) = (f^−1∘g^-1)(x) works with matrices as well: (AB)^-1 = B^-1 A^-1
*January 26, 2016*

**Calculus**

Assuming you meant x instead of h, V = 1/3πx^2(18-x) = 6πx^2 - 1/3πx^3 dV/dx = 12πx - πx^2 the jar's volume is 400π cm^3. If it drains in π seconds, that's 400cm^3/s. That is dV/dt dV/dt = (12π - 2πx) dx/dt -400 = (12π-...
*January 26, 2016*

**Marble hall**

sure. why not?
*January 26, 2016*

**Math**

x/2 + 16 = 36
*January 25, 2016*

**math**

{a,b}∪{a,c} = {a,b,c} {a,c,d}∩{b,d,e} = {d} {abc}×{d} = {ad,bd,cd} In part b, since the two sets have no elements in common, the intersection is empty.
*January 25, 2016*

**Calculus**

1/y + 1/x = 1 + y^2 -1/y^2 y' - 1/x^2 = 2y y' (-1/y^2 - 2y)y' = 1/x^2 y' = (1/x^2)/(-1/y^2 - 2y) = -(1/x^2)/((1+2y^3)/y^2) = -y^2 / (x^2(1+2y^3)) -(x^2/y^2) -x^2 y^-2 -2x y^-2 + 2x^2y^-3 y' 2x(x-y)/y^3 y' no equation, but that's where we are so far.
*January 25, 2016*

**College Algrebra**

or, consider this a normal work problem: 1/60 + 1/66 = 1/t t = 220/7
*January 25, 2016*

**Math**

240/16 = 15 so, the rectangle is 15 tiles long. 60/15 = 4 so the rectangle is 4 tiles wide. Thus, it is 4*16 = 64 cm across
*January 25, 2016*

**Math**

4p/3 - 5
*January 25, 2016*

**math**

4:1 = 12:3 now you can tell which ratio is greater
*January 25, 2016*

**Math**

(1-7)/(18-(-2)) = -6/20
*January 25, 2016*

**Algebra**

The scale is 3ft/in, so the real-life dimensions are 15ft:6ft The area is thus (5in*2in)*(6ft/2in)^2 = 10*3^2 = 90 ft^2
*January 25, 2016*

**Math**

without actually doing a regression, check the average slope: (255-183)/(79-67) = 6 84-79=5, so 255+6*5 = 285 b is closest to that value.
*January 25, 2016*

**Math**

looks ok to me
*January 25, 2016*

**Math**

mark each pair on a number line. > means "to the right of" < means "to the left of"
*January 25, 2016*

**math**

seems simple enough to me 350/260 = 35/36 Now it's clear that the answer is 1 9/26 since 35=26+9
*January 25, 2016*

**Math- Urgent, please help!**

before posting the question and your answer, did you try actually using your number to see whether it worked in the equation?
*January 25, 2016*

**Math**

d + d+3 = 17
*January 25, 2016*

**MATH HELP MS SUE OR SOMEONE**

every line segment joining two points on a circle is a chord. So, every diameter is a chord. chords do not have to pass through the center.
*January 25, 2016*

**Math**

f◦g = 2^g = 2^(3-x) = (2^x)/8 g◦f = 3-f = 3-2^x the domain of all exponentials is all reals. The range of all a^x is (0,∞) see where that leads.
*January 25, 2016*

**math**

or, to keep in scientific notation, 5.14x10^6
*January 25, 2016*

**Calc help!**

put it all over a common denominator. How do you add 2/3 + 5/7 ? You use the common denominator of 3*7. Do this the same way.
*January 25, 2016*

**Maths**

that's vertices, not testices. The circumcenter lies at the intersection of the sides' perpendicular bisectors. So, to start, find the equations of two of the bisectors. AB: slope=1/3 midpoint is (7/2,7/2) pb: (y-7/2) = (-3)(x-7/2) AC: slope=4 midpoint is (5/2,5) pb: (...
*January 25, 2016*

**maths**

not unique, since 2^2 3^4 5^2 or 5^2 3^4 2^2 a+b = 2+3 = 5 or a+b = 5+3 = 8
*January 25, 2016*

**math**

9 + x <= 14 x <= 5
*January 25, 2016*