A COOL MATH TRICK-- GETTING nth TERM OF AN AP
Our Major Goal:
finding nth term of an AP with a cool trick.
One More goal :
Turning aah! into ahaa!!
Given:
The sum of an AP in "n" form will be given.
SO LET US PROCCEED.....AND SEE HOW THE QUESTION COMES:
The Question:
Q: The sum of an AP is given by 3n^2 + 5n. find the nth term of it.
Our Usual Approach:
Putting n = 1, got first term........and then n = 2, getting the sum, and then subtracting it.
When doing it in exam, seeting the time.....you say uh!, shortage of time!!!
The SMARTY Approach:
Add the coeffecients of n^2 and n i.e. 3 + 5 which gets 8. Now remember 8 for a moment.Now multiply the power of 1st n i.e. 2 with its coeffecient i.e. 3 , so we get 3*2 = 6. now think that how much it takes for 6 to get 8(We remembered).....it takes 2 because 6+2 = 8. So write it in this form:
6n + 2
6 becomes coeffecient of n and it is added with 2 to make the sum of 6 and 2 be equal to the sum of 5 and 3(the one given in question).
This would not take more than 30 sec. for an average student.
This method is likely an aaha!! Approach!!
FOR MY OTHER TRICKS GO TO THESE LINKS:
Some trigonometry tips and tricks
6 becomes coeffecient of n and it is added with 2 to make the sum of 6 and 2 be equal to the sum of 5 and 3(the one given in question).
This would not take more than 30 sec. for an average student.
This method is likely an aaha!! Approach!!
FOR MY OTHER TRICKS GO TO THESE LINKS:
Some trigonometry tips and tricks
