Math Is Fun Forum

  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

#1 Help Me ! » Application of integral » 2009-04-16 05:29:43

Danbee
Replies: 1

Find the volumes of the solid generated by revolving the regions about the given axes?
The region bounded by y= -x+3 and y=x² -3x about
a) the x-axis
b)the y-axis

#2 Re: Help Me ! » Application of definite integrals » 2009-03-28 04:33:57

Or rather the statement I made is

π∫_(-1)^1▒(1-x^2 )^2  dx=8π/5  but that is not the right answer ofr the (a) part of the question. I wonder where I got it all wrong.

#3 Re: Help Me ! » Application of definite integrals » 2009-03-28 04:29:08

I solved it this way but got the wrong answer.

π∫_(-1)^1▒〖1-x^4 〗 dx=8π/5

#4 Help Me ! » Application of definite integrals » 2009-03-28 04:18:19

Danbee
Replies: 2

Find the volume of the solid generated by revolving the region bounded by the parabola y=x²  and the line line y=1

a. about the line y=1
b.about the line y=2
c. about the line y=-1

#6 Help Me ! » Application of integral » 2009-03-13 05:45:40

Danbee
Replies: 3

The curve y=x³, 0≤ x≤ 3, is rotated about the y-axis. What volume does the resulting surface enclose? Use x as the dependent variable.

#7 Help Me ! » Applications of integral » 2009-02-26 03:18:55

Danbee
Replies: 0

Write the integral that represents the surface area of a hemisphere of radius one and evaluate it.

#8 Help Me ! » Application of integrals » 2009-02-18 06:20:37

Danbee
Replies: 1

Calculate the volume of a solid with base in the plane an equilateral triangle of side 1, with base on the x-axis, and with vertical cross section parallel to the y-axis consisting of an equilateral triangle.

#9 Help Me ! » Methods of integration » 2009-02-12 07:49:07

Danbee
Replies: 1

Evaluate the following indefinite trignometric integral.


∫sin² x cos² x dx

#10 Help Me ! » Integral » 2009-02-05 03:21:19

Danbee
Replies: 1

Evaluate the integral.



                               ∫_3^5▒dx/(x.log⁡(x))

#12 Help Me ! » Improper integral » 2009-01-06 05:53:59

Danbee
Replies: 2

Evaluate the following improper integral, be sure to write the integral as an appropriate limit.



∫_0^3▒sinx/x^2 dx

#13 Help Me ! » Indeterminate forms in Calculus » 2009-01-02 05:02:03

Danbee
Replies: 2

A trust is established in your name which pays t+10 dollars per year for every year in perpetuity, where t is time measured in years ( here the present corresponds to time=0). Assume a constant interest rate of 4%. What is the total value, in today's dollars,of all the money that will be earned by your trust account?

Beacuse of inflation, the value of a dollar decreases as time goes on.Indeed this decrease is directly related to the continuos compounding of interest

#15 Help Me ! » Application of derivative » 2008-12-05 12:19:25

Danbee
Replies: 4

Find the right circular cylinder of greatest volume that can be contained in a sphere of radius 1

#16 Help Me ! » Natural logarithm » 2008-11-21 07:44:03

Danbee
Replies: 2

Can any body explain to me how the first equation arrives to be the second:



lnx/(x-1)=ln〖x^((1⁄(x-1))  〗

#17 Help Me ! » Permutations and combinations » 2008-11-06 07:24:14

Danbee
Replies: 1

On a math test a student is to select any four out of ten problems of equal difficulty. the test contains 2 geometry, 3 algebra, 1 statistics, and 4 probability problems.


How many different four-problems selections are possible if each selection includes the same number of algebra problems as probability problems?

#18 Help Me ! » Permutations and combinations » 2008-11-06 05:39:34

Danbee
Replies: 2

The student government at central high school consists of 4 seniors, 3 juniors, 3 sophomores, and 2 freshmen. How many different nine-student committees can be formed that include, at most, one freshman?

#20 Help Me ! » Permutations and combinations » 2008-11-06 04:19:42

Danbee
Replies: 2

A bookshelf contains six mysteries and three biographies. In how may ways can two books be selected so that at least one of the books is a mystery book?

#21 Help Me ! » Geometric sequence and series » 2008-11-05 12:18:59

Danbee
Replies: 1

The first term of a geometric sequence is 27, and the sixth term is 519/9.

find the seventh term

#22 Re: Help Me ! » Permutations and combinations » 2008-10-31 13:33:10

Thanks for the solution . That is the right answer!

#23 Help Me ! » Permutations and combinations » 2008-10-31 13:29:59

Danbee
Replies: 2

The telephone company has run out of seven-digit telephone numbers for an area code.To fix this problem, the company will introduce a new area code. Find the number of new seven -digit telephone numbers that can be generated for the new area code if both of the following conditions must be met:


CONDITION 1: The first digit cannot be 0 or 1
CONDITION 2: The first three digits cannot be the emergency number (911) or the number used for the information (411)

#25 Help Me ! » Permutations and combinations » 2008-10-31 06:07:39

Danbee
Replies: 5

How many four-digit even numbers can be formed if no digit is repeated?

Board footer

Powered by FluxBB