st

Monday, April 6, 2009

finding sin( arctan(2) )

find sin(arctan(2) )
let A = arctan(2) ------------------(1)
tanA = 2 = 2 / 1
use these on a triangle with side opposite to A as 2, adjacent to A as 1
use pythagoras theorem to get the hypotenuse sqrt(5)

so sin A = 2 / sqrt(5)

using equation(1)
sin ( arctan(2) ) = 2 / sqrt(5) = [ 2*sqrt(5) ] / 5



-----------------------------------------------------------
please leave your comments below
------------------------------------------------------------
index of math problems


disclaimer:
There is no guarantee about the data/information on this site. You use the data/information at your own risk. You use the advertisements displayed on this page at your own risk.We are not responsible for the content of external internet sites. Some of the links may not work





Saturday, April 4, 2009

approximation of an integral using binomial series

using three terms of the binomial expansion of 1 / sqrt[ 1 - x^3] ,
evaluate the integral of 1 / sqrt[ 1 - x^3] with limits 0 to 0.5

binomial series is
here n = -1/2 , x should be replaced with ( - x^3)


-----------------------------------------------------------
please leave your comments below
------------------------------------------------------------
index of math problems


disclaimer:
There is no guarantee about the data/information on this site. You use the data/information at your own risk. You use the advertisements displayed on this page at your own risk.We are not responsible for the content of external internet sites. Some of the links may not work





Thursday, April 2, 2009

cricket

Cricket is a game which is popular in India.
It is also popular in england, australia, west indies, new zealand,sri lanka, pakistan, bangladesh, south africa, zimbabwe and in most of the former colonies of britain.
The older format is test cricket played over a period of five days, consisting of a maximum possible of two innings per team.
The shorter formats are mainly 50 over a side one-dayers (usually takes around 7 hours)
and the still shorter 20 over a side 20-20.
live cricket scores are usually available at cricinfo.com
icc test rankings are usually available at icc-cricket.yahoo.net

in the old days test cricket played in india was usually shown live on doordarshan
but after large scale commercialisation, it shifted to private pay channels like star sports
soon after espn came into the picture
after that many other sports channels like ten sports, star cricket, zee sports channel, neo sports have come up.
even some channels like set max and sahara which usually show so called hindi serials/ films etc have to subscribed to if you want to watch some of the cricket matches
a list of some tv channels available in india

Wednesday, April 1, 2009

answers to questions on time and work

Time and Work

Answers

1. 12 days

2. 6 days

3. 1.5 days

4. 21children

5. 48 hours

6. 1200 men

7. 50 men

short notes on time and work

back to questions on time and work

-----------------------------------------------------------
please leave your comments below
------------------------------------------------------------
index of math problems


disclaimer:
There is no guarantee about the data/information on this site. You use the data/information at your own risk. You use the advertisements displayed on this page at your own risk.We are not responsible for the content of external internet sites. Some of the links may not work





some problems on time and work

Time and Work



1. A man working alone can do a piece of work in 20 days while a woman working alone can do the same piece of work in 30 days. In how many days will the work be completed if the man and woman work together?

2. 'A' can do a piece of work in 9 days. If 'B' is 50% more efficient than A, find the number of days required by B to complete the piece of work?

3.A and B can respectively do a piece of work in 20/3 days and 5 days. They work together for 2 days and then A leaves . How many more days will it take for B to complete the work?

4. If 3 men and 5 women can do a piece of work in 8 days, and 2 men and 7 children can do the same piece of work in 12 days, then find how many children's work in a day is equal to the work of 10 women in a day?

5.Two pipes A and B can separately fill a tank in 12 hours and 16 hours respectively. A third pipe C can empty the tank in 8 hours. If all the three pipes are left open, how much time will it take for the tank to be filled?

6. A garrison has enough food for 52 days. After 20 days, 400 more soldiers arrived at the garrison. Now for the increased number of soldiers the food will last for only 24 days. How many soldiers were there originally in the garrison?

7. 40 men can dig a ditch 20m X 10m X 1m in 50 days. How many men will be required to dig another ditch 25m X 8m X 1m in 40 days ?

answers

short notes on time and work



-----------------------------------------------------------
please leave your comments below
------------------------------------------------------------
index of math problems


disclaimer:
There is no guarantee about the data/information on this site. You use the data/information at your own risk. You use the advertisements displayed on this page at your own risk.We are not responsible for the content of external internet sites. Some of the links may not work





relation between eigen values of A and its inverse matrix

If k is an eigen value of a non singular matrix , then (1 / k) is an eigen value of its inverse



-----------------------------------------------------------
please leave your comments below
------------------------------------------------------------
index of math problems


disclaimer:
There is no guarantee about the data/information on this site. You use the data/information at your own risk. You use the advertisements displayed on this page at your own risk.We are not responsible for the content of external internet sites. Some of the links may not work








Saturday, March 21, 2009

integral of (secx)^4

integral of (secx)^4

split into( sec²x )( sec²x )

change one of the factors into 1+ tan²x
split into two integrals
one is a direct formula integration formulae

for the other integral use substitution method
-----------------------------------------------------------
please leave your comments below
------------------------------------------------------------
index of math problems


disclaimer:
There is no guarantee about the data/information on this site. You use the data/information at your own risk. You use the advertisements displayed on this page at your own risk.We are not responsible for the content of external internet sites. Some of the links may not work





SAT Conditional Probability Trick: Master “Given That” Questions Fast

  🎯 SAT Conditional Probability: The Hidden “Given That” Trick Conditional probability looks complicated on the SAT because the question of...