Friday

August 28, 2015
Total # Posts: 33,101

**algebra**

a+2d = 5 a+6d = 13 d=2, so a+29d = a+6d+23d = 13+(23*2) = 59
*August 11, 2015*

**physics**

a = ∆v/∆t = (10.5 m/s)/(3.18s) = 3.20 m/s^2
*August 11, 2015*

**physics**

Just solve for t: 3.38 + 3.29t - 4.9t^2 = 0
*August 11, 2015*

**Physics**

I'll do (a) and (b). The other plane is similar. Since the plane is flying at an angle of 15° upward, the tank when released as a velocity of 185sin15° = 47.88 m/s vertically 185cos15° = 178.70 m/s horizontally How long does it take the tank to hit the ground? ...
*August 11, 2015*

**physics**

All you know is that the ratio of their sines is 1.4 Unless you know one of the angles, you cannot determine the other.
*August 11, 2015*

**Urgent math pls**

In the first place, you have your ratio backwards. 119-108 = 11 dB So, the intensity is 10^1.1 = 12.6 times as much.
*August 11, 2015*

**Urgent math quick**

Are you using a linear temperature function, or Newton's rule for cooling? If linear, then since the turkey cooled 35° in 1/2 hr, then it will cool another 17.5° in the next 15 minutes. 150-17.5 = 132.5° It would have helped had you shown your calculations. I ...
*August 11, 2015*

**geometry**

well, r^2 = x^2+y^2, so ...
*August 10, 2015*

**algebra**

b = 2c (b-5)+(c-5)=26 2c+c=36 c=12 So, bert is 24
*August 10, 2015*

**calculus**

y"' = 24x-6 y" = 12x^2-6x+2a y' = 4x^3-3x^2+2ax+b y = x^4-x^3+ax^2+bx+c Now what else do we know? y(-1) = 8 y(1) = 4 y'(1) = 4 So, 1+1+a-b+c = 8 1-1+a+b+c = 4 4-3+2a+b = 4 Solve for a,b,c and you have y = x^4-x^3+2x^2-x+3 I'll let you verify that it ...
*August 10, 2015*

**advance function**

I assume you want to prove that they are equal tan/sin = sec so, sec^2 = 1+tan^2 that is one of your fundamental identities, obtained by dividing by cos^2 in sin^2 + cos^2 = 1
*August 10, 2015*

**Math**

You are correct.
*August 10, 2015*

**Math**

so, yes, you are correct. Sorry -- I didn't notice your answer.
*August 10, 2015*

**Math**

remember that y=mx+b is called the slope-intercept form. Parallel lines have the same slope.
*August 10, 2015*

**calculus**

y"= 6x-4 y' = 3x^2 - 4x + a y = x^3 - 2x^2 + ax + b y(1) = 2 and y(-2) = 5, so 1-2+a+b = 2 -8-8-2a+b = 5 a = -6, b=9, so y = x^3 - 2x^2 - 6x + 9
*August 10, 2015*

**Math**

The digit in the tens place is 4. xxx4x One of the digits has a value of 700. xx74x The value of the digit in the thousands place is 10 times greater than this. x774x There is 1 less ones than tens. x7743 57743 What was so hard about that? You just have to read, and put the ...
*August 10, 2015*

**math**

3^2 + 2(3)(ab) + (ab)^2 x(x+1) - 2(x+1) - 12(2x+1) + 3x(2x+1) just expand those out and collect like terms
*August 10, 2015*

**am I gualify for boiler maker?**

Naturally, the same could be said for any other profession. :-)
*August 10, 2015*

**Statistics Please Help**

Since the bell curve is symmetric, you have p(0<Z<c) = .4868 Look up .4868 and you see that c=2.221 Or, you can see that 1-.9736 = .0264. Half of that is 0.0132 Add that to the .9736 and you have .9868 Look that up, and you have Z=2.22 You can play around with Z table ...
*August 10, 2015*

**Algebra II**

but, (5-6) = -1, so we have -1 + 14/7 = -1+2 = 1
*August 10, 2015*

**Calculus**

y' = sin 2x
*August 10, 2015*

**Algebra**

if you have y = 3x(x+4), then shrink it by multiplying by 1/5 y = 3x / 5(x+4) since 1/(5x) is shrunk compared to 1/x
*August 10, 2015*

**English**

thank you
*August 9, 2015*

**English**

"I submit that an individual who breaks a law that conscience tells him is unjust, and who willingly accepts the penalty of imprisonment in order to arouse the conscience of the community over its injustice, is in reality expressing the highest respect for law." In ...
*August 9, 2015*

**Sociology**

thank you
*August 8, 2015*

**Sociology**

What are necessary to explain research findings? a- variables b-theories c- symbols d- research models I'm not sure of the answer because you would need models to conduct the research and theories to model the research. I don't think symbols would explain the findings ...
*August 8, 2015*

**Sociology**

Are theories necessary to explain research findings? My answer is yes.
*August 7, 2015*

**Sociology**

thank you
*August 7, 2015*

**Sociology**

only 19th century sociologists addressed social problems. only 19th century sociologists tested their theories with systematic research. ancient civilizations were egalitarian and did not address class differences. war and social conflict were a product of the industrial ...
*August 7, 2015*

**Sociology**

One of the primary differences between the study of Society done by the people of ancient civilizations and the study of society conducted by sociologists 19th century was what?
*August 7, 2015*

**math**

thank you
*August 7, 2015*

**math**

if point a = -7 and b = 8 what is their length? my answer is 15
*August 7, 2015*

**Geometry**

In a line with points a,b,c,d what is the name of the ray that is opposite ba? my answer is ca
*August 7, 2015*

**Geometry**

plane hkp and plane rkp are 2 distinct planes. Name the intersection of plane hkp and rkp my answer is line kp
*August 7, 2015*

**English**

In both the Gettysburg Address and “Letter from Birmingham Jail,” the writers comment on the tribulations faced by a nation at war. honor those who have fought for freedom. demand the revision of the nation’s unjust laws. expound on the notion of tolerance for ...
*August 6, 2015*

**English**

What 3 selections below were purposes that caused martin Luther King jr to write the Letter From the Birmingham Jail? 1- defend his actions 2- react to a statement 3- explain his religious views 4- share his opinions regarding segregation my answers are 1,2,and 4
*August 6, 2015*

**World History**

Which of the following is NOT true about bias? Answer: a) Using both biased and non-biased resources in research will create bias results b) Bias can be identified by the facts that the Web site includes as well as the facts that are excluded c) In a biased web site it is ...
*August 5, 2015*

**English**

thank you
*August 4, 2015*

**English**

What Is the correct mla format for a book in a works cited list? My answer last name first name book title city of publication date
*August 4, 2015*

**English**

Is a clause a part of speech? My answer is no.
*August 3, 2015*

**English**

Thank you
*August 3, 2015*

**English**

I'm sorry I meant C
*August 3, 2015*

**English**

Archetypes frequently appear in literature with - a- contradictory themes b- general themes c- universal themes d- specific themes my answer is D
*August 3, 2015*

**Mathematics**

we know that (5a+12b)^2 + (12a+5b)^2 = (13a+kb)^2 25a^2+120ab+144b^2 + 144a^2+120ab+25b^2 = 169a^2 + 26kab + k^2b^2 169a^2+240ab+169b^2 = 169a^2+26kab+k^2b^2 (240-26k)ab + (169-k^2)b^2 = 0 b((240-26k)a+(169-k^2)b) = 0 Since a and b are positive, either 249-26k < 0 or 169-k^...
*July 30, 2015*

**trig**

tanx = 3 so, sinx = 3/√10 cosx = 1/√10
*July 30, 2015*

**Math**

After t days, you have 100*(1/2)^t
*July 30, 2015*

**Math**

280(4mi)^2 = 280*16 mi^2
*July 30, 2015*

**maths**

(1) no algebraic way to do it. Check the graph (2) 2x+2y < 4 3x+4y > 6 Just plot the lines and shade the areas that intersect (3) clearly x=100
*July 30, 2015*

**math**

Why do you say "for some reason"? Didn't you solve the problem? Did you check your answer? 500-70+10 = 440 = 500 * 0.85 ok 300-30+75 = 375 = 345 * 1.15 ok Here's how I did it. I imagine you did it in much the same way. to start, 500 ducks 300 chickens then ...
*July 30, 2015*

**Calculus**

well, 1-sin^2 = cos^2, so you have cos^2θ - sin^2θ = cos 2θ cos^2θ * sin^2θ = 1/4 sin^2(2θ)
*July 30, 2015*

**Calculus**

I see some algebra and trig, but no calculus also, no question
*July 30, 2015*

**What did I did wrong MATH**

(3x-6)/(4x+12) = 1/3 it takes 12 fifty-cent coins to be "the same amount" as six dollar coins
*July 30, 2015*

**Algebra I I**

sure looks like substitution to me.
*July 30, 2015*

**math**

5^(x+2) = (5^x)(5^2) = 7*25 = 175 However, as you wrote it, 5^x+2 = 7+2 = 9 Parentheses are important!
*July 30, 2015*

**math**

clearly, -2001 <= x <= 0 Thus, 0 <= x+2001 <= 2001 So, how many numbers between 0 and 2001 are squares? √2001 = 44.7 So, There are 45 numbers such that 0 <= x <= 44, meaning that 0 <= x^2 <= 2001
*July 30, 2015*

**math**

√1000000 = 1000 √4000000 = 2000 any number less than 1000 has a square less than 1 million any number greater than 2000 has a square greater than 4 illion so, you want all the numbers n such that 1000 < n < 2000
*July 30, 2015*

**math, hard**

who's talking about square roots? These are absolute values. |a| = -a, so a = -|a| same for b. So, a-b = -|a| - (-|b|) = -|a| + |b|
*July 30, 2015*

**math! VERY hard!**

3/4 = 9/12 1/3 = 4/12 so, you already have 13/12lbs of fruit You still need 1 11/12 = 23/12 lbs That is 9/12 + 14/12 = 3/4 + 6/12 + 8/12 = 3/4 + 1/2 + 2/3
*July 30, 2015*

**Math**

tanx+cotx = sec^2x/tanx = 1/(sinx cosx) secx+cscx = (sinx+cosx)/(sinx cosx) so, we have sinx+cosx + 2/sin2x + 2(sinx+cosx)/sin2x See what you can do with that
*July 30, 2015*

**Trig**

sinx+cosx = 1/5 square both sides and you have sin(2x) = -24/25 so, cos(2x) = -7/25 Now you can use your half-angle formula for tan(x)
*July 30, 2015*

**Trig**

Take a look here: http://www.maths.surrey.ac.uk/hosted-sites/R.Knott/Fibonacci/fibpi.html and scroll down to Sec. 6.2
*July 30, 2015*

**Math**

Since sinx is always less than 1, you need to find where x^2/625 >= 1 There will be no solutions past that. Looks like you don't need to look beyond x=25. So, how many periods does sinx have in that domain? Looks like 4, positive and negative, so I expect there are 15 ...
*July 30, 2015*

**Math**

If the pirate is at horizontal distance x from the building, at the hill has height h, then (400-h)/x = tan 4° h/x = tan 2° Eliminate h and you have 400 - x tan4° = x tan2° Now you can find x. Assuming the pirate can fly horizontally, that is the shortest ...
*July 30, 2015*

**trigo - eh?**

midway is in the middle; same distance on each side which is taller, the near or far? Is "c" supposed to mean angle?
*July 30, 2015*

**maths**

what the heck is the radius of the area of a semicircle
*July 30, 2015*

**Trig**

draw your triangle. If the legs of the triangle are x+1 and x-1, the hypotenuse is √((x+1)^2 + (x-1)^2)) = √(2x^2+2) so, sin(arctan((x+1)/(x-1)) = (x+1)/√(2x^2+2)
*July 30, 2015*

**Trig**

Recall your sum/difference formulas. You have sin(2x-y)+sin(y) = 2sin(x)cos(x+y) cos(2x-y)+cos(y) = 2cos(x)cos(x+y) Now just divide and you have tan(x)
*July 30, 2015*

**Math**

0 and 180π/(180+π)
*July 30, 2015*

**Math**

f(t^2+1) = t^4+5t^2+3 = (t^2+1)(t^2+4) - 1 = (t^2+1)((t^2+1)+3)-1 That means that f(t) = t(t+3)-1 So, f(t^2-1) = (t^2-1)((t^2-1)+3)-1 = t^4+t^2-3
*July 30, 2015*

**Math**

clearly, f(2003) = 0, since f(f(0)) = 0
*July 30, 2015*

**maths**

pi not pai!! d/dx u^v = v*u^(v-1)u' + lnu u^v v' You have u=x and v=x^10 ∫[-2,-1]∫[0,1] x^2y^2+cos(πx)+sin(πy) dy dx = ∫[-2,-1] 1/3 x^2 y^2 + cos(πx)*y - 1/π cos(πy) [0,1] dx = ∫[-2,-1] 1/3 x^2 + cos(πx) + 2/π ...
*July 30, 2015*

**Trigonometry**

recall the law of cosines. The distance z will be z^2 = 20^2 + 44^2 - 2*20*44*cos100°
*July 30, 2015*

**math**

why all the words? a = x^2+x-42 Factor that to get a = (x+7)(x-6)
*July 30, 2015*

**math - eh?**

and then? and is your + key not working?
*July 29, 2015*

**Algebra II**

correct
*July 29, 2015*

**calc**

so, is F(x) = ∫[1,3x] ln(t^2) dt or F(x) = ∫[1,3x] (ln t)^2 dt ? Either way, f(x) = F'(x) = ln(3x)^2 * 3 or f(x) = F'(x) = (ln 3x)^2 * 3 And F" = f' Recall that the 2nd Fundamental Theorem of Calculus says that if F(x) = ∫[a,g(x)] f(t) dt ...
*July 29, 2015*

**math algebra**

if p>2 is prime, p is odd So, p+999 is even, so it cannot be prime.
*July 29, 2015*

**Calculus - Rate of Change**

the cone has volume v = 1/3 π r^2 h = 1/3 πr^3 dv/dt = πr^2 dr/dt when v = 1000, r = ∛(3000/π) so, 10 = π(3000/π)^(2/3) dr/dt now you can find dr/dt, and since r=h, that's also dh/dt
*July 29, 2015*

**trig**

Good catch. a^2+b^2 = 64, not 8
*July 29, 2015*

**trig**

c^2 = a^2+b^2 = 64 ab/2 = 8 (a+b)^2 = a^2+2ab+b^2 = 8+32 = 40 p = a+b+c = 8+√40
*July 29, 2015*

**Calculus**

craft travel on a heading, not a bearing. 700 @ N23°E = (273.51,644.35) 60 @ E = (60,0) Add them up and you have (333.51,644.35) = 725.55 @ N27.36°E
*July 29, 2015*

**Math - My Bad**

Oops. I misread the diagonal part. Could not help the gibberish, however.
*July 29, 2015*

**Math**

area of parameter is gibberish area = (8√10)(3*8√10) perimeter = 2(8√10 + 3*8√10)
*July 29, 2015*

**calculus**

x^2+16x < 0 x(x+16) < 0 You know the graph crosses the x-axis at x=0,-16. So, x(x+16) < 0 if -16<x<0
*July 29, 2015*

**Geometry**

That's some field!
*July 29, 2015*

**maths**

You appear to want x^4+3x-2 -------------------------- (x^2+1)^3 (x-4)^2 You manage to mangle things badly, and the solution to that fraction has been posted in response to an earlier version of the poorly typed question. Here it is again. http://www.wolframalpha.com/input/?i...
*July 29, 2015*

**College Algebra**

ln x = 6 x = e^6 ln(e^2) = 2*ln(e) = 2*1 = 2
*July 29, 2015*

**College Algebra**

You probably have a yx button on your calculator. Use it. Or, note that (2/3)^x = e^(ln(2/3)*x) = e^(-0.4055x) Now you can use your e^x button to evaluate the expressions. And it's pi, not pie!
*July 29, 2015*

**College Algebra**

1/5 log(x+3)^5 = log(x+3) log(x^6)-log(x^2-x-12)^3 = 3log(x^2/(x^2-x-12)^3) = log((x^2)/(x^2-x-12)) so, adding those logs, we have log(x+3) + log((x^2)/(x^2-x-12)) = log(x^2(x+3) / (x+3)(x-4)) = log(x^2/(x-4))
*July 29, 2015*

**College Algebra**

log(a^b) = b*log(a) log(u/v) = log(u)-log(v) So, you have 5log(x)-log(y)-6log(z) where all the logs are base a.
*July 29, 2015*

**maths**

60sin(40°) The ship is east of the starting point. Your question is worded backwards.
*July 29, 2015*

**Solving Geometry Formulas**

this is just like the last one. What do you get?
*July 29, 2015*

**maths**

((6+3)(4+3)-(6*4))(0.1) = 3.9 m^3
*July 29, 2015*

**maths**

If npr=3024, r=3024/np y' = (secx-tanx)/(secx+tanx) y' = (secx-tanx)^2/tan^2x y' = csc^2x - 2cscx + 1 Those are straightforward integrals
*July 28, 2015*

**trig**

5pi/4 = pi/4 + pi So, if you can find the terminal point in QI (pi/4), just change the sign of x and y to put it in QIII.
*July 28, 2015*

**Solving Geometry Formulas**

2(7+L) = 56 7+L = 28 L = 21
*July 28, 2015*

**MATHS**

the width has grown by a factor of 4/3 so, the volume has grown by a factor of (4/3)^3
*July 28, 2015*

**Math**

I think this is an example of logistic growth, since the population will rise sharply until the food supply gives out, limiting further growth. I'm not really up on curve fitting for logistic growth, but the general curve is y = 1/(1+(1/a-1)e^(-rt)) where a is y(0)/y(&#...
*July 28, 2015*

**maths**

for area, our new area is 4pi(.99r)^2 So, if we divide that by the original area, we have 4pi(.99r)^2 / 4pir^2 = .99^2 1-.99^2 = 0.0199 That is, a 1.99% decrease in area Note that the area decreases by about twice the percentage as the radius. I think you can expect the volume...
*July 28, 2015*

**Algebra**

assuming that f(x) = ax^3+bx^2+cx+d, d=47 a+b+c+47 = 32 8a+4b+2c+47 = -13 27a+9b+3c+47 = 16 f(x) = (52x^3 - 201x^2 + 104x + 47)/3
*July 28, 2015*