Let the value of the given expression:
4 + 2 3 − 4 − 2 3 , be n .Find n .
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And also can you recommend me some websites online that can help me ?
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www.imomath.com Its a nice website for good questions.Try it once.
Indeed, Dinesh's recommended website is good, but it's a little "too hard" for you right now.
Check out this huge list and also this specific olympiad , along with one of the best websites that you could ever find something to study .
EDIT: Lorenc, add me up on Facebook.
Facebook is driving me crazy i dont know why but i cant make you my friend did you block something anyway can you make me friend?
Guilherme Dela Corte , i have another method to solve these kind of problems.For example for this problem that i posted my solution was: Let the value be x.Squaring both sides two times a row after some operations with square roots we obtain x 4 = 4 . where x = 4 1 / 4 or 2 .About your problems i think that the first one can be solved applying the same method and for the others i do not have a general solution .Please i am in 8th grade this year and i want to learn as much as i can about mathematics.If you know how to solve them please show your solution.
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Lorenc, just call me Guilherme . :D
Solutions:
a : We can see that ( 3 ± 2 ) 4 = 4 9 ± 2 0 6 . This means a = 3 + 2 + 3 − 2 ⇒ a = 1 2 . This problem was created by the famous Indian math genius Ramanujan .
b : Squaring both sides, we get 2 + 2 + 2 + ⋯ = b 2 . But 2 + 2 + ⋯ = b , so 2 + b = b 2 . This results in b = 2 .
c : This one can be solved by using functions. Let c = α x + ( n + α ) 2 + x α ( x + n ) + ( n + α ) 2 + ( x + n ) ⋯ . Squaring both sides leads us to c 2 = α x + ( n + α ) 2 + x α ( x + n ) + ( n + α ) 2 + ( x + n ) ⋯ . Allowing c = F ( x ) , we have F ( x ) 2 = α x + ( n + α ) 2 + x ⋅ F ( x + n ) , and it can be proved that F ( x ) = x + n + α . Letting α = 0 , n = 1 , x = 2 , we have c = 3 . This problem also came from Ramanujan. Check out a study about it in this presentation , from pages 8 to 1 4 .
d : Cube both sides to get d 3 = 6 + 3 6 + 3 6 + 3 ⋯ . But 3 6 + 3 6 + 3 ⋯ = d , so d 3 = 6 + d . It is clear that d = 2 . .
Lorenc, NEVER GIVE UP STUDYING !
EDIT: Lorenc, add me up on Facebook.
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Answer: We can see that
4 + 2 3 = ( 1 + 3 ) 2
4 − 2 3 = ( 1 − 3 ) 2
Thus we can simplify the expression to 1 + 3 + 1 − 3 ⇒ 2 = n ⇒ n = 2 .
Comments: this is a very cool problem, which can be expanded to fit harder exercises. This one is very good for a low-level Algebra student.
Lorenc (and also other readers), can you solve these ones?
4 4 9 + 2 0 6 + 4 4 9 − 2 0 6 = a , find a .
2 + 2 + 2 + ⋯ = b , find b .
1 + 2 1 + 3 1 + 4 ⋯ = c , find c .
3 6 + 3 6 + 3 6 + 3 ⋯ = d , find d .