Sunday

August 30, 2015
Total # Posts: 30,686

**math functions**

All three are correct #3 is correct assuming you are starting with n = 1
*May 4, 2015*

**Math**

Very simple LS = sin^2 x - cos^2 x = sin^2x - (1-sin^2 x) = 2sin^2 x - 1 = RS
*May 3, 2015*

**math**

Angles do not have area.
*May 3, 2015*

**trigonometry**

Did you not read my post? I told you how to do it.
*May 3, 2015*

**trigonometry**

let's just tackle the LS LS = sin(A+B)*sin(A-B) = (sinAcosB + cosAsinB)(sinAcosB - cosAsinB) = sin^2 Acos^2B - cos^2Asin^2B , the difference of squares pattern = (1 - cos^2A)(cos^2B) - cos^2A(1-cos^2B) = cos^2B - cos^2Acos^2b - cos^2A + cos^2Acos^2B = cos^2B - cos^2A = RS ...
*May 3, 2015*

**Math**

done look back when you posted it earlier
*May 2, 2015*

**trigonometry**

one rotation is 2π so -31π/6 ÷ 2π = -5 - π/6 so we have 5 clockwise rotations and another clockwise of π/6 (remember in trig, counterclockwise is positive and clockwise is negative) or consider the rotations in degrees 31π/6 radians = 930&...
*May 2, 2015*

**trigonometry**

Since arctan and tan are inverse operations, then logically arctan(tan(-31π/6)) = -31π/6 however .... since it probably wants the angle closest to the origin, and since tan(-31π/6) = tan(-π/6) arctan(tan(-31π/6) = arctan(tan(-π/6) = -π/6
*May 2, 2015*

**Math - Trigonometry**

Ls = 1/cosx - cos^2 x/cosx = (1-cos^2 x)/cox = sin^2 x/cosx = sinx sinx/cox = sinx tanx = RS How can you change 1/cosx - cosx to 1/cosx - cosx/cosx ?? you can't just toss in an extra cosx at the bottom that last term of cosx/cosx would reduce to 1
*May 2, 2015*

**Math - Trigonometry**

I have helped you with two of these now. I think it is time for you to try them. Hint: on the LS, find a common denominator and add the two terms Show me your steps and I will help you from there.
*May 2, 2015*

**Math - Trigonometry**

This one's really easy ... RS = sin^2 x - cos^2 x = sin^2 x - (1 - sin^2 x) = 2sin^2 x - 1 = LS
*May 2, 2015*

**Math - Trigonometry**

LS = 1/sinx + 1/cosx = (cosx + sinx)/(sinxcosx) = (cosx + sinx)(1/sinx)(1/cosx) = (cosx+ sinx)(cscx)(sec) = RS
*May 2, 2015*

**Calc 1**

Wasn't your tangent line supposed to pass through the origin?
*May 2, 2015*

**algebra**

well, let's just take the slope using the 2 given points slope = (y-2)/(3-1) = (y-2)/2 but we are told that the slope is 2 , so (y-2)/2 = 2 y-2 = 4 y = 6
*May 2, 2015*

**algebra**

what is (1/2)(1/2)(1/2) ?
*May 2, 2015*

**Math Calc**

You will need the vertex of this parabola I don't know what method you learned , so I will use the simplest way not using Calculus for y = ax^2 + bx + c, the x of the vertex is -b/(2a) so for yours, t = -112/-32 = 3.5 sub that back in to get the maximum height. when it ...
*May 1, 2015*

**math**

What is the question? Is this supposed to be an equation looking like 3x^2 - 27x^2 + 60x = 0 ?
*May 1, 2015*

**Math**

yes, you got it. it would be x = nπ/2, where n is an integer.
*May 1, 2015*

**Math**

since csc Ø = 1/sinØ csc (2x) has asymptotes when sin(2x) = 0 (the amplitude won't matter) sin(2x = 0 then 2x = 0 , ±π, ±2π , ±3π .... x = 0 , ±π/2, ±π, ±3π/2 ... http://www.wolframalpha....
*May 1, 2015*

**Calculus**

just notice that 0 < a < 4, so our answers would be the two shown in my solution a = 1.11415714 and a = 2.772605
*May 1, 2015*

**Calculus**

no, you were right the first time if y = x + cos(ax) , then dy/dx = 1 - asin(ax) so for a max, asin(ax) = 1 but we are told that x=1 a sin a = 1 sin a = 1/a very hard equation to solve, if you have a good calculator, set it to radians and start trying some values. clearly a &#...
*May 1, 2015*

**math**

Let's see how many cubes we can lay along the length, 4.5 ÷ .25 = 18 and along the width, 5 ÷ .25 = 20 and how high can we stock them? 3.75 ÷ .25 = 15 So there would be 18 x 20 x 15 of them or 5400 (and you spent 3 hours on this? not possible!) another...
*April 30, 2015*

**Math 12**

A four-of-a-kind is four cards showing the same number plus any other card. If we order the 5-card hand with the four-of-a-kind first, we have C(13,1) choices for the number showing on the first four cards. Since we will have all four suits, we have only C(4,4) = 1 way to ...
*April 30, 2015*

**Math Check**

No Prob(first is white) = 4/14 = 2/7 now there are only 13 socks left, so prob(2nd is blue) = 8/13 prob(1st white, then blue) = (2/7)(8/13) = 16/91
*April 30, 2015*

**math homework**

that's better, that would simply be 4 x 5 x 2 or 40 ways
*April 30, 2015*

**math homework**

This question makes no sense. You say that there are "about" 5 different Star Wars issus, "about" 5 ..... and then you ask for "exactly" how many .... Please clarify.
*April 30, 2015*

**math**

Betty ? Kyle ? , please stick to one name No, how can it be simply 40 when the first answer was 59280 ?? You are just guessing and hope that I will give you the solution. Look at my solution for the first one, and tell me why my second multiplier is only 39 instead of 40 and ...
*April 30, 2015*

**math**

yes, the first one. How would you do the second one ? How would the solution change ?
*April 30, 2015*

**math**

yes, remember there were actually two questions. Which of the two did we answer, and how would you do the other one?
*April 30, 2015*

**math**

so there are 40 numbers to pick from. first choice -- 40 2nd choice -- 39 3rd choice -- 38 what is 40*39*38 ?
*April 30, 2015*

**Math**

surely you have those in your text or notes. first one: term(n) = a + (n-1)d and you know both a and d term(n) = 4 + (n-1)(8) = 4 + 8n - 8 = 8n - 4 for the second, go to your text, find the formula for term(n) of a GS , and plug in your given values
*April 30, 2015*

**ALGEBRA**

part at 4% --- x part at 5% --- 7500-x .04x + .05(7500-x) = 325 after you multiply each term by 100 to get rid of the decimals this is an easy equation to solve. Go for it.
*April 30, 2015*

**ALGEBRA**

prob(repair) = 3/100 expected cost = (3/100)($39) = $1.17 cost of agreement = $9.00 so profit per agreement = 7.83 Percentage of profit = 7.83/9 = .87 or 87% (not bad, that is why I never buy these agreements) another way to look at it. Suppose 100 people bought the agreement ...
*April 30, 2015*

**math**

First make a sketch, here is Wolfram's version http://www.wolframalpha.com/input/?i=y+%3D+cosx+%2B+1%2Fcosx+for+-%CF%80+to+%2B%CF%80 The vertical lines are asymptotes, and thus will not yield any values. You can see that the min value is appr 2 Here is a larger picture, ...
*April 30, 2015*

**math**

1 + 4x + 4x^2 - 16x^4.. ,1 + 2x - 8x^3 - 16x^4.., 16x^4 + 4x^2 + 1 is there a significance to the .. at the end of the first term? if not, then 1 + 4x + 4x^2 - 16x^4 = (1+4x) + 4x^2(1 - 4x^2) = (1 + 4x) + 4x^2(1 - 2x)(1 + 2x) 1 + 2x - 8x^3 - 16x^4 = (1+2x) - 8x^3(1 + 2x^2) 16x...
*April 30, 2015*

**Math**

every pair of same factors must be a perfect square and any integer base raised to an even exponent must be a perfect square, so all factors are perfect square except 7^15 which is 7^14 x 7 7^14 is a perfect square, but if I multiply that by 7 it no longer is. we could write ...
*April 29, 2015*

**Please help -_-**

Sadie, there was only about 1 hour between the time you first posted this and your second posting. Have some patience, we are volunteers and don't sit here all the time just waiting for questions. In my case I might come here a few times a day, if I see questions ...
*April 29, 2015*

**Calculus-limits**

since the power of the numerator is one degree higher than that of the denominator we get y = (9x-x^2-7x^4)/(x^3+12x) = -7x + ?? so as x gets bigger, y gets bigger, so the limit is undefined, (approaches negative infinity, or we can say the limit does not exist
*April 29, 2015*

**easy math**

done, always check back before reposting
*April 29, 2015*

**Math**

Assuming he picks one topping number = 2 x 16 x 2 = 64
*April 29, 2015*

**mathssss**

I will assume you mean: (2c+5)/-5 * (2c+5)/-5 + (4c-2)/5 * (4c-2)/5 = 20 major difference from what you typed, those brackets are critical (4c^2 + 20c + 25)/25 + (16c^2 - 16c + 4)/25 = 20 20c^2 + 4c + 29 = 500 20c^2 + 4c - 471 = 0 solve using the formula
*April 29, 2015*

**math**

lw = 60 ---> l = 60/w 2l + 2w = 38 ---> l + w = 19 60/w + w = 19 times w 60 + w^2 = 19w w^2 - 19w + 60 = 0 (w-15)(w-4) = 0 w = 15 or w = 4 , then l = 4 or l = 15 the length is 15 and the width is 4
*April 29, 2015*

**Algebra**

always check back before reposting http://www.jiskha.com/display.cgi?id=1430287921
*April 29, 2015*

**Calculus**

For any point (a,b) |12a - 9b - 5| /√(144+81) = 2 12a - 9b - 5 = 30 12a - 9b = 35 Now test which ordered pair satisfies this linear equation.
*April 29, 2015*

**algebra 2**

no matter what the function f(x) ---> f(x-5) results in a horizontal translation of 5 units to the right look at the graph http://www.wolframalpha.com/input/?i=plot+y+%3D+log%28x%29+%2C+y+%3D+log%28x-5%29+for+0%3C+x%3C30
*April 29, 2015*

**math**

arc length of a circle = rØ, where Ø is in radians 5Ø = 10 Ø = 2 radians or appr 114.59°
*April 29, 2015*

**Math**

looks like experimental , and the results don't match the theoretical or mathematical probability When rolling a die, the real prob(5) = 1/6
*April 29, 2015*

**Analytic Geometry**

given: 4x+3y - 10 = 0 a) easiest way: since the new line is parallel it must look like 4x+3y + c = 0 using your distance formula from a point to a line |4(2) + 3(-1) + c|/√(4^2 + 3^2) = 3 8 - 3 + c = 15 c = 10 4x + 3y + 10 = 0 or -8 + 3 - c = 15 -c = 20 c = -20 4x + 3y...
*April 29, 2015*

**Math**

Wasn't there an "experiment" of rolling the dice 160 times? And it came up "2" 39 times So the experimental prob must be 39/160 The theoretical probability is the actual mathematics one, so the "2" is one of the 6 sides, so the experimental ...
*April 29, 2015*

**ALGEBRA**

distance = √( (4-(-2))^2 + (-5-3)^2 ) = √(36 + 64) = √100 = 10
*April 29, 2015*

**Algebra**

25000(.8)^n = 5000 .8^n = .2 take log of both sides , and using log rules n log.8 = log.2 n = log .2/log .8 = appr 7.2 years
*April 29, 2015*

**Algebra**

Choc chip -- 12 oatmeal ---- 12 no-bake ---- 12 peanut butter --12 gingerbread ---12 Sample space = C(60,6) selections of six gingerbread from 12 = C(12,6) prob = C(12,6)/(C(60,6) = .000018456
*April 28, 2015*

**Math**

Did you check if the slope between any two points is always the same ? Hint: the point (0,0) is a good point to check in the given equations. Which equation does it satisfy ?
*April 28, 2015*

**Math**

I suggest you make a table of sums for 6 rows and 6 columns from the numbers from 1 to 6 Fill in the sums, e.g. the first row and last row would be 2 3 4 5 6 7 .... 7 8 9 10 11 12 count up all the odd ones, obviously 18 of them Remember 2 is a prime number so it must be ...
*April 28, 2015*

**Math**

In the first one I think Bob forgot about the other 5 cards that have to be drawn I am going to do these by using combinations P(exactly 2 wild, 5 non-wild) = ( C(8,2) x C(100,5) / C(108,7) = .0756 or using bob's method P(exactly 2 wild, 5 non-wild = 8/108 * 7/107 * 100/...
*April 28, 2015*

**math**

make a sketch and let our point needed be (x,y) for the x: (x-(-5))/(6-x) = 2/3 3x + 15 = 12-2x 5x = -3 x = -3/5 for the y: (y+4)/(-2-y) = 2/3 3y + 12 = -4-2y 5y = -16 y = -16/5 your point is (-3/5 , -16/5) or, using vectors (x,y) = (3/5)(-5,-4) + (2/5)(6,-2) = (-3 , -12/5...
*April 28, 2015*

**maths**

2a + 2m = 5a + m so m = 3a if 3a = m and m = 2.40 3a = 2.4 a = .8 So each apple costs 80 cents, and a mango $2.40 check: 2apples + 2 mango = 1.60 + 4.80 = 6.40 5apples + 1 mango = 4.00 + 2.40 = 6.40 yes, they are equal My answer is correct
*April 28, 2015*

**mathematics**

Kayla, in your solution you defined variables but then never used them Jerry's marbles --- x Tom's marbles ---- 4x Ali's marbles ---- 4x + 36 their sum is 279 x + 4x + 4x+36 = 279 9x = 243 x = 27 Jerry has 27 marbles Tom has 108 marbles Ali has 144 marbles Tom has ...
*April 28, 2015*

**Algebra**

10t^5 + 5t^4 - 50t^3 = 0 t^3( 2t^2 + t - 10) = 0 t^3(2t+5)(t-2) = 0 t = 0 or t = -5/2 or t = 2
*April 27, 2015*

**Algebra**

well, you created the perfect square on the left, so state it , and simplify the right side (x - 3/8)^2 = -39/64 ahhh, I see the problem. How can anything squared be negative, so there is no REAL number solution. Have you studied complex numbers? If so, then x - 3/8 = ±...
*April 27, 2015*

**Algebra**

repeat the procedure I just showed you, tell me what you got.
*April 27, 2015*

**Algebra**

divide by 2 and bring constant to the right side x^2 - 3x + .... = 18 x^2 - 3x + 9/4 = 18 + 9/4 (x - 3/2)^2 = 81/4 x - 3/2 = ± 9/2 x = 3/2 ± 9/2 x = -3 or x = 6
*April 27, 2015*

**College Algebra**

You defined x as the price, but did not use it as such I will re-define x as the number of $1 increases new price = (100+x) number of rooms rented = 95-x Revenue = R(x) = (100+x)(95-x) = 9500 - 5x - x^2 R ' (x) = -5 - 2x = 0 for a max of R(x) 2x=-5 x = -2.5 I will assume ...
*April 27, 2015*

**Calculus**

the hardest part is finding the intersection of the two curves, x^2 - 1 = cosx I will let Wolfram do it: http://www.wolframalpha.com/input/?i=x%5E2+-+1+%3D+cosx Because of the symmetry we could go from 0 to 1.1765 and double the answer area = 2 ∫(cosx - x^2 + 1)dx from 0...
*April 27, 2015*

**Math 222**

Stop switching names and stick to one name only -x^2 - 3x + 5 = 0 x^2 + 3x - 5 = 0 use the quadratic formula x = (-3 ± √29)/2
*April 27, 2015*

**The villages**

I will take a giant leap of faith and assume you want it simplified, (x+3)/(x^2-2x-8)- (x-5)/(x^2-12x+32) = (x+3)/((x-4)(x+2)) - (x-5)/((x-4)(x-8)) LCD is (x-4)(x+2)(x-8) = [(x+3)(x-8) - (x-5)(x+2)]/((x-4)(x+2)(x-8) ) = ... expand the top and simplify / (x-4)(x+2)(x-8)
*April 27, 2015*

**Algebra**

Now: Dana ---- x Renee --- 2x 4 years ago: Dana = x-4 Renee = 2x-4 "Four years ago Renee was three times as old as Dana" ---> 2x-4 = 2(x-4) solve for x, very straight-forward
*April 27, 2015*

**Math, please help**

insufficient data
*April 27, 2015*

**Math**

−22.75 cos (π/6(m − 1)) + 52.55 = 48 -22.75 cos ((π/6)(m-1)) = -4.55 cos ((π/6)(m-1)) = .2 ((π/6)(m-1)) = 1.369438... or ((π/6)(m-1)) = 4.9137459.. m-1 = 2.61543.. or m-1 = 9.38456.. m = 3.615435 or m = 10.38457 adding/subtracting 2π ...
*April 27, 2015*

**Math help!**

hint: multiply each term by 6x and rearrange.
*April 27, 2015*

**Math help!**

x of the vertex is -b/(2a) -----> good formula to memorize = -(-16)/(4) = 4 f(4) = .... so now you have the vertex. easy to read off the max/min and the axis of symmetry. for x intercept let y = 0 in y = 2x^2 - 16x + 27 for y intercept let x = 0 in y = 2x^2 - 16x + 27 ...
*April 27, 2015*

**Math help!**

miles on the highway --- x miles in the city ----- 465-x gallons used on highway = x/24 gallons used in city = (465-x)/18 x/24 + (465-x)/18 = 23 multiply each term by 72 , the LCD 3x + 4(465-x) = 1656 3x + 1860 - 4x = 1656 -x=-204 x = 204 Miles on the highway were 204 check: ...
*April 27, 2015*

**Math help!**

number of dimes ---- x number of quarters -- 43-x 10x + 25(43-x) = 760 etc.
*April 27, 2015*

**polynominals**

1975 ---> x = 5 y = 5^2 + 3(5) + 2 = 42 million repeat for the other years (silly question, assumes the number of trout keeps increasing, e.g. in 2020 we would have 50^2 + 3(50)+2 or 2652 million trout)
*April 27, 2015*

**probability**

3 red 2 green 4 white 2 purple ---> total = 11 let's do the prob that she had the 3 reds number of such choices = C(3,3) x C(8,5) = 56 number of choices of 8 from 11 = C(11,8) = 165 prob(all 3 reds) = 56/165 so prob(not all the reds) = 1 - 56/165 =109/165
*April 27, 2015*

**Math 222**

Was not meant to be scarcastic, simply trying to figure out the best way to explain it, there are several ways.
*April 27, 2015*

**Math 222**

first equation: -5x + 2y = 16 subbing in y = 2x+7 ----> -5x + 2(2x+7) = 16 -5x + 4x + 14 = 16 -x = 2 x = -2 now put that back into y = 2x+7 = 2(-2) + 7 = 3 all done curious, at what grade level are you taking this?
*April 27, 2015*

**Math 222**

-5x+2y=16 y = 2x+7 Tika, Doesn't the 2nd equation tell you what the value of y is ?? Just replace the y in the 2y of the first equation with the value of y in the second. Give it a try, it is really easy. Let me know what you got.
*April 27, 2015*

**Math**

since sinØ = opposite/hypotenuse = -3/5 you should recognize the 3-4-5 right-angled triangle. You are also told the the angle (or triangle) is in the I, II, or IIIrd quadrant. But isn't sinØ negative only in III of those given? so x = -4, y= -3 thus tan&...
*April 27, 2015*

**Math 222**

solve each one separately if you want 2x-1 ≥ -3 2x ≥ -2 x ≥ -1 4x+5 ≥ -19 4x ≥ -24 x ≥ -6 but they are connect with AND, so ... x ≥ -1 AND x ≥ -6 Now thing about, what numbers are both greater than or equal to -1 AND -6 Place the...
*April 27, 2015*

**MATH**

This question makes little sense to me. Are the times given based on how long each one could row the boat? Why would you let Dale row for 10 minutes, if Abby ran do it it 1 minute? Anyway, taking your data at "face-value" .... A=1 B=2 C=5 D=10 I would use A for all ...
*April 27, 2015*

**Math 222**

rate charged by first mechanic --- x rate charged by second mechanic -- y "sum of their rates is 165" ---> x+y = 165 "first mechanic worked 10 hours" ---> 10x "the second mechanic worked 5 hours" --- 5y "Together they both charged a ...
*April 27, 2015*

**Math 222**

-2x + 9y = 3 -3x - 4y = 22 first equation times 3 -6x + 27y = 9 second equation times -2 6x + 8y = -44 add the new equations: 35y = -35 y = -1 sub back into original -2x + 9y = 3 -2x - 9 = 3 -2x = 12 x = -6 x= -6 , y = -1 of course you should realize that there are many other ...
*April 27, 2015*

**Math 222**

Both our last two replies posted at the same time. NO, both numbers are NOT 12 Look at your question, it said one is 23 less than the other, how can they be both 12 ? This is why definitions of your variable are so important. I defined by smaller as x, so it is 12 I defined by...
*April 27, 2015*

**Math 222**

yes, that would be one of the answers, remember it asked for two answers. You should verify your answers against the original conditions to eliminate any doubt
*April 27, 2015*

**Math 222**

smaller number --- x larger number ----- x+23 x + x+23 = 47 easy to solve....
*April 27, 2015*

**math**

How did you decide it was B ?
*April 27, 2015*

**Statistics PLEASE HELP**

prob(both defective) = (2/8)(1/7) = 1/28 prob(at least one good) = 1 - 1/28 = 27/28
*April 27, 2015*

**math**

True , the surface area of similar objects is proportional to the square of the sides (1/2)^2 = 1/4
*April 26, 2015*

**Math**

multiply each term by 3 3y + 9 = x x - 3y - 9 = 0
*April 26, 2015*

**calculus check**

correct
*April 26, 2015*

**Calculus**

how about L'Hopital's Rule limit = 7/( (1/2)(x+4)^-(1/2) ) = 14(√(x+4) = 14(2) as x---> 0 = 28
*April 26, 2015*

**Calculus**

number ' (t) = 100e^t + 75t number (t) = 100e^t + (75/2)t^2 + c assuming at opening (t=0) no people were in the zoo, 0 = 100e^0 + (75/2)(0) + c c = -100 number(t) = 100e^t +(75/2)t^2 - 100 so when t = 2.666.. (at 9:40 am) number(2.666...) = 100e^2.6667 + 37.5(2.666..) - ...
*April 26, 2015*

**Analytic Geometry**

slope of 1st line = (-2-6)/(5+1) = -8/6 = -4/3 slope of 2nd line = (7+4)/(1-3) = -11/2 angle made by 1st line = tan^-1 (-4/3) = 126.87° angle made by 2nd line = tan^-1 (-11/2) = 100.30° angle between them = 26.565° or tan(angle between) = (-4/3 + 11/2)/(1 + (-4/3...
*April 26, 2015*

**algebra**

9(x^2 - 8x + ....) + 4(y^2 + 4y + ....) = -124 9(x^2 - 8x + 16) + 4(y^2 + 4y + 4) = -124 + 144 + 16 9(x-4)^2 + 4(y+2)^2 = 36 divide each term by 36 (x-4)^2 /4 + (y+2)^2 /9 = 1
*April 26, 2015*

**Math**

18sin^2 Ø +3cosØ - 17 = 0 18(1- cos^2 Ø) + 3cosØ - 17 = 0 18 - 18cos^2 Ø + 3cosØ -17 = 0 18cos^2 Ø - 3cosØ -1 = 0 (6cosØ + 1)(3cosØ - 1) = 0 cosØ = -1/6 or cosØ = 1/3 Ø = 1.738.. or &...
*April 26, 2015*

**math**

Sales of the $12000 which are over $5000 = $7000 so total commission = .06(5000) + .12(7000) = ..
*April 26, 2015*

**math**

Let the side parallel to the highway be y ft let each of the other two sides be x ft So 2x + y = 680 y = 680-2x area = xy = x(680-2x) = 680x - 2x^2 which is a parabola opening downwards, and you want its vertex. Since you are doing this type of question, you must have learned ...
*April 26, 2015*

**calculus**

integral of (3x^2+2x+4) dx f(x) = x^3 + x^2 + 4x + C given (f(1) = 10 10 = 1 + 1 + 4 + C C = 4
*April 26, 2015*

**Calculus**

need their intersection: x^2 - 4x + 3 = x + 4 x^2 - 5x - 1 = 0 was hoping for "nicer" values, but anyway.... x = (5 ± √29)/2 height of our region within those x values = x+4 - (x^2 - 4x + 3) = 1 + 5x - x^2 area = ∫(1 + 5x - x^2)dx from x = (5-&#...
*April 26, 2015*