Which number should come next? 144 ,121, 100, 81, 64 __?
9 Feb 07
For a polynomial of order less than 5 49 is the only fit. For an order 5 polynomial fit, ANY of the alternatives given could fit. In fact a 5th order polynomial fit can be found for 144,121,100,81,64,u where u is any value you care to choose. Consider this. A 5th order polynomial is of the form ax^5 + bx^4 + cx^3 + dx^2 + ex + f. 6 unknowns. a unique solution is a certainty for ANY value of u.
13 Feb 07
It shoud be defintely 49 you took it this way: 144-121=23 121-100=21 100-81=19 81-64=17 and then the last number 64-(__)=15 that is 64-49=15 49 should be the perfect match for this problem continuing the series of odd numbers from 23-15
10 Feb 07
is this a number sequences? my answer is 49 because 144 is perfect square of 12, 121 is perfect square of 11, 100 is perfect square of 10, 81 is perfect square of 9, 64 is perfect square of 64, so perfect square of 7 is 49. correct!!!!!
10 Feb 07
The correct answer is 49, and that's from the choices letter "d". Well it is an arithmetic progression with numbers having differences of also arithmetic progressing odd numbers starting 23, 21, 19, 17, and 15. Well, you have made a unique discussion. I believe you are fond of mathematics. For me, its been a routine exercises when I studied Civil Engineering in my college years. Now that I am a Professional Civil Engineer already, its a great recall of those tricky math problems you have just posted. You are definitely unique. Hear you around my friend.