Saturday

February 25, 2017
Total # Posts: 48,776

**mathematics**

and . . .

*January 15, 2017*

**Algebra2**

If you mean f(x) = 2x^2+x-3 then f(g) = 2g^2+g-3 = 2(x-1)^2+(x-1)-3 = 2x^2-3x-2

*January 14, 2017*

**Algebra2**

f(x)2x^(2)+x-3 g(x)=x-1 Perform the indicated operation, then find the domain (f*g)(x)

*January 14, 2017*

**Education**

Thank you very much

*January 14, 2017*

**Education**

The single best way to increase your income is to get an education. Why? 1- You automatically make more money if you are educated. 2- You automatically get promotions if you are educated. 3- You can obtain jobs that have higher starting salaries. 4- You will automatically ...

*January 14, 2017*

**Calculas**

x?¹-1 = 1/x - 1 = (1-x)/x So, your fraction is just (1-x)/x ---------- = -1/x x-1

*January 14, 2017*

**Physisc**

A 12 kg mass initially moving at 4 m/s is acted upon by a 120 N constant force. What is the final speed of the mass?

*January 14, 2017*

**Applied calculus**

the other dimension is (2000-2x)/2 = 1000-x I assume you know how to express the area of a rectangle.

*January 14, 2017*

**Calculus**

see related questions below.

*January 14, 2017*

**Math**

looks ok to me.

*January 14, 2017*

**math**

W = kL That is, W/L is constant. So, you want W such that W/14 = 105/7

*January 14, 2017*

**math**

what do you mean by A=50? A is an angle of ABC. Same for P P is a point. What do you mean by "find P"? If you want lengths of sides given the lengths of bisectors, then review the angle bisector theorem.

*January 14, 2017*

**Arithmetic progression**

"sum" not "some" Assuming you meant had she got 3 more in maths and 4 marks less in science I tried m+s = 28 (m+3)(s-4) = 180 If that's what you meant, then just solve for m and s.

*January 14, 2017*

**Maths**

the length+width must be 8. So, how many pairs of numbers add to 8? 1+7 2+6 ...

*January 14, 2017*

**physics**

The somewhat vague requirements give rise to the following equations of motion: a = 2/3 v + (2/3)t = 25 vt + (1/3)t^2 = B-A or 25t - 1/3 t^2 = B-A Without knowing how long it took to get from A to B (only knowing that it is less than 75/2 seconds - why?), that's all we can...

*January 14, 2017*

**Algebra**

-1375 + 450 = ?

*January 13, 2017*

**Algebra**

you should recognize those numbers as perfect squares.

*January 13, 2017*

**Calculus**

well, f'(Ø) = 2secØ tanØ + sec^2Ø = sec^2Ø(2tanØ cosØ + 1) = sec^2Ø(2sinØ+1) f'(Ø)=0 when sinØ = -1/2 Now, what else is a critical number?

*January 13, 2017*

**Calculus**

Think about what you know about the shape of |x| functions. They have a cusp, where the slope is discontinuous.

*January 13, 2017*

**Precalc**

when cos(pi/6 (t+2)) = -1 That is, where pi/6 (t+2) = pi

*January 13, 2017*

**Algebra 1**

try this: http://calc101.com/webMathematica/long-divide.jsp

*January 13, 2017*

**Calculus**

check your text or google to review what differentiable means.

*January 13, 2017*

**Algebra**

1 ok 2 is 7 < 3? 3 "<" means less

*January 13, 2017*

**math**

2x-4 = x+11

*January 13, 2017*

**maths**

well, there will be two days that occur 53 times. So, ...

*January 13, 2017*

**dynamics of rigid bodies**

I'll assume you meant s = 5t^2 + 1/3t^3 -1/50t^4 so, v = 10t + t^2 - 2/25 t^3 max v occurs when v'=0, so a = 10 + 2t - 6/25 t^2 So, find t when a=0, and then figure v at that value of t. max acceleration is when a'=0 a' = 2 - 12/25 t

*January 13, 2017*

**math**

15% of original, (.15*24000) or 15% off original ((1-.15)*24000) ??

*January 12, 2017*

**Calculus**

h = u/v h' = (u'v-uv')/v^2 Now just let u = 3x+2 v = x^2-5 Now each step is easy.

*January 12, 2017*

**Riddle**

well, you said her mom kept 6

*January 12, 2017*

**pre-algebra**

depends on what you mean by solve the question. Drawing a graph is one way to illustrate the relation between x and y. Another way is to fill in a table of matching values. Pick values for x and calculate the matching y values. Other questions might be to determine the axis ...

*January 12, 2017*

**math**

it is an odd function, so it is symmetric about (0,0)

*January 12, 2017*

**Geometry**

just use the distance formula.

*January 12, 2017*

**Precalculus**

well, every 2pi brings theta back to the same point, so ...

*January 12, 2017*

**math unit 7 test**

it should be clear that the inside of the arch cannot be covered by another arch.

*January 12, 2017*

**math**

ask google many many discussions

*January 12, 2017*

**Math**

5 ...

*January 12, 2017*

**Graphing in the coordinate plane unit test**

try google on some key topics...

*January 12, 2017*

**algebra**

try here. It shows all the steps. http://calc101.com/webMathematica/long-divide.jsp

*January 12, 2017*

**Mathematical measurement**

sure looks like 5:12 to me

*January 12, 2017*

**Computing**

n=1 s=1 for (i=1;i<=5;i++) { print s; n += 2; s += n }

*January 12, 2017*

**Computing**

depends on what information you want No idea what the "output of a triangle" is

*January 12, 2017*

**C**

add the numbers and divide by 10. If they are in an array called n, then sum=0 for (i=0 to 9) sum += n[i] avg = sum/10

*January 12, 2017*

**math**

4x-6 = x+15

*January 12, 2017*

**Physical science**

use the lengths as the legs of a right triangle. But, if the are not acting perpendicularly, you're out of luck.

*January 12, 2017*

**math8**

-9p-17=10 -9p = 27 p = -3 too bad you didn't bother to show your work.

*January 12, 2017*

**math**

the roots of D^2-6D+3 are -3±?6

*January 12, 2017*

**Maths**

5*9 = 45

*January 12, 2017*

**Maths**

what are two small factors of 45?

*January 12, 2017*

**Linear Algebra**

google the topic. You will find many good discussions, such as this one: http://math.stackexchange.com/questions/584132/proof-of-linear-independence-of-vectors-after-applying-a-linear-transformation

*January 12, 2017*

**Math**

us the law of cosines. You have two sides and the included angle.

*January 12, 2017*

**Algebra 2 check my answer please?**

500*2^(t/16) = 800 2*(t/16) = 1.6 t/16 log2 = log 1.6 t/16 = log1.6/log2 = 0.67807 t = 10.849

*January 12, 2017*

**Algebra**

what, you can't just plug in the number and find t? 0.81t^2 = 3 t^2 = 3/.81 = 3.7037 t = 1.9245

*January 12, 2017*

**math**

3*(2*6 + 2*8)

*January 12, 2017*

**sdsdd**

91/100

*January 12, 2017*

**4th grade math**

well, 5+15 = 20

*January 12, 2017*

**Calculus**

forget the integral. It's not elementary. besides, no one asked what f(x) was. The question was, where does it achieve its minimum value?

*January 11, 2017*

**Math**

e^(-?i) = cos(-?)+ i sin(-?) = -1

*January 11, 2017*

**Algebra**

it's the same as the number of ways to permute 2 of 3 things: 3P2 = 6

*January 11, 2017*

**Math**

c^2 = a^2+b^2 a = 1/2 bh If the perp from B to AC is BD, then using similar triangles, BD/AB = BC/AC

*January 11, 2017*

**Math**

assuming you meant speed (since the average velocity is zero after every lap!) You are correct. The distance covered is 352*1.5 Since it took four hours, the average speed is 352*1.5/4 mi/hr You can use the derivative if you insist, but since this is apparently a linear ...

*January 11, 2017*

**math**

y-1 = 3(x+2) y-1 = 3x+6 y = 3x+7 -7 = 3x-y 3x-y = -7 Looks like (A) to me

*January 11, 2017*

**math**

the slope is 3, so the point-slope form is y-1 = 3(x+2) or y-10 = 3(x-1) Now just massage that into one of the choices.

*January 11, 2017*

**IPC**

98 * 1.49/9.8

*January 11, 2017*

**Maths**

since their longitude differs by 180°, the lie on the same great circle, which passes through both poles. It would have been more challenging to prove that they lie on a slanted great circle.

*January 11, 2017*

**Science**

50m/2.8s = 50/2.8 m/s = ...

*January 11, 2017*

**Calculus Please Help**

Assuming the x values for the table are 1,2,3,4 then d/dx g(f(2x)) = g'(f(2x)) * f'(2x) * 2 = g'(f(2)) * f'(2) * 2 = g'(1) * 2 * 2 = 5*2*2 = 20 consider something like y = e^sin(2x) y'(x) = e^sin(2x) * cos(2x) * 2

*January 11, 2017*

**Calculus**

looks good to me

*January 11, 2017*

**Calculus**

Hmmm. h is constant at 12, so V = ?r^2h = 12?r^2 dV = 24?r dr ...

*January 11, 2017*

**Math parallel lines and angles**

no diagrams visible here. Just recall what you know about alternate angles and adjacent angles of transversals.

*January 11, 2017*

**Angle Math Help!**

well, you could always consider the 5-12-13 right triangle.

*January 11, 2017*

**Geometry**

I don't see how YO can divide the square. It just goes from a side to the center.

*January 11, 2017*

**Math Calc**

Hmmm 3.14*4.2^2 * 12.2 = 665.75 other than that, your logic is sound. Also, note that the error using 4.0-0.2 in for the low-side value differs by a smaller amount.

*January 11, 2017*

**Math Calc**

if 3.8 <= r <= 4.2, ?*3.8^2*12 <= v <= ?*4.2^2*12 544.32 <= v <= 665.01 ...

*January 11, 2017*

**math algebra**

15.99 + 0.93m = 259.65

*January 11, 2017*

**Calculus**

see the further discussion on your earlier post.

*January 11, 2017*

**Calculus**

That is because x=0 is the single point where f'(x) = 0 the number zero is a single choice, not an absence of choices! The answer is 1 There is 1 (one) point on the interval [-1,1] where f(1)-f(-1) ------------ = 0 1 - (-1) That point is at x=0. Just take a deep breath and...

*January 11, 2017*

**Calculus**

Excuse me? Did you look at the graph? Did you actually read what I wrote? I don't mind helping you arrive at a solution, but I do expect you to actually read it, rather than just hold out your hand and say "gimme the answer." In fact, I did give you the answer.

*January 11, 2017*

**Calculus**

absolute value problems can get tricky, because the functions are not differentiable at any cusps. However, since (x^2-9)(x^2+1) is negative on [-1,1], f(x) = -(x^2-9)(x^2+1) This is a nice smooth polynomial, so it satisfies the requirements of the MVT on [-1,1]. Now take a ...

*January 11, 2017*

**Calculus**

v(t) = 0 at 0,?,2? If you exclude the endpoints of the interval, your answer is correct. But, we are working with the closed interval, including the endpoints. So, there are 3 points where v(t) = 0. Better review interval notation.

*January 11, 2017*

**Calculus**

v(x) = -sin(x) e^cos(x) since e^cos(x) is never zero, how many times in sin(x) = 0 in the interval? Your answer is correct on the interval (0,2?), but not on [0,2?]

*January 11, 2017*

**Vectors**

This is discussed here: http://math.stackexchange.com/questions/1408917/finding-vector-form-of-an-angle-bisector-in-a-triangle

*January 11, 2017*

**Maths**

Using x and y for syntactical reasons, See http://www.wolframalpha.com/input/?i=%7B%7B7,9%7D,%7B5,7%7D%7D*%7B%7Bx%7D,%7By%7D%7D+%3D+%7B%7B3%7D,%7B1%7D%7D

*January 11, 2017*

**Calculus**

try (lim x^3) * (lim sin(1/x)) x^3 -> 0 |sin(1/x)| <= 1

*January 11, 2017*

**Maths**

1 degree of latitude is about 111 km. So, 800 km/hr ? 800/111 = 7.2°/hr so, ...

*January 11, 2017*

**Maths**

Check the diagram. The radius of the latitude at angle ? is r*cos?. Since speed is proportional to the radius of rotation, if B is at angle ?, r cos22° = 2r cos?

*January 11, 2017*

**math;););)**

so, do you know the rotation matrix?

*January 11, 2017*

**Math;);)**

Actually, it's even better than that: |u + v|^2 ? |u|^2 + |v|^2 ? (|u|+|v|)^2

*January 11, 2017*

**Calculus**

since when is x^2/x^2 = 2? 10/10 = 1 z^3/z^3 = 1 don't forget your Algebra I now that you're taking calculus. Using the usual method, divide top and bottom by x^2. That gives you (1 + 2/x^2)/(1 - 36/x^2) as x^2 gets huge, 1/x^2 -> 0 and the fraction becomes 1/1 NOT 2!!

*January 11, 2017*

**Calculus**

as x gets huge, the 2 and the 36 become insignificant: y -> x^2/x^2

*January 11, 2017*

**Physics**

40 S = <0,-40> 70 N30ºW = <-35,60.6> add them up, then convert back to compass directions.

*January 11, 2017*

**Math**

1700 * .96*9

*January 10, 2017*

**calculus**

a = t^2-5t+3 v = 1/3 t^3 - 5/2 t^2 + 3t + C1 s = 1/12 t^4 - 5/6 t^3 + 3/2 t^2 + C1*t + C2 Now use the conditions to solve for C1 and C2.

*January 10, 2017*

**pre-Calculus**

a: odd b: even c: unknown check by using the fact that odd: f(-x) = -f(x) even: f(-x) = f(x)

*January 10, 2017*

**Math**

100/(b+24)

*January 10, 2017*

**Trig**

If the base is 2x, then 12.5/x = tan 55° The area is just 12.5x

*January 10, 2017*

**Math**

-.25x^2+5.5x-5.25 = -1/4 (x^2-22x) - 21/4 = -1/4 (x^2-22x+121) - 21/4 + 121/4 = -1/4 (x-11)^2 + 25

*January 10, 2017*

**Math**

8C4

*January 10, 2017*

**Math**

w(w+5) = 50 Now, which factors of 50 differ by 5?

*January 10, 2017*

**Algebra**

4a-2b+c = 5/2 c = 3/2 16a+4b+c = -121/2 F(x) = -5/2 x^2 - 11/2 x + 3/2

*January 10, 2017*