can anyone help me with this problem as well as give a clear explanation? thank you!!
Find the value of
\(x = 1 + \cfrac{1}{2 + \cfrac{1}{2 + \cfrac{1}{2 + \cfrac{1}{2 + \ddots}}}}.\)
I didn't manage to write the answer of this question by any mathematical ways, nor by using my hand, but the function gets closer and closer to \(≈ 1.41421356237\) as more layers are added, which equals to \(\sqrt2\).
This is also the reason that \(\sqrt2\) is an irrational number instead of a rational one, since it needs infinite fractions to express it.
Program: http://www.wolframalpha.com/input/?i=1%2B1%2F(2%2B1%2F(2%2B1%2F(2%2B1%2F(2%2B1%2F(2%2B1%2F(2%2B1%2F(2%2B1%2F(2%2B1%2F(2%2B1)))))))))
Add 1 to both sides
x + 1 = 2 + [ 1 / [ 2 + [ 1 / [ 2 + 1 / [ ... ]
Now...let x + 1 = y
But...y = [ 2 + [ 1 / [ 2 + 1 / [ ... ]
So...we have that
y = 2 + [1 / y ] multiply through by y
y^2 = 2y + 1 rearrange
y^2 - 2y - 1 = 0
Solving this with the quadratic formula gives that y = 1 + √2 or y = 1 - √2
But since the right side of the original problem is positive then so is x
And since x + 1 = y then x = y - 1
So y must = 1 + √2
So...... x = [ 1 + √2 ] - 1 = √2
P.S. - thanks to one of our members - geno - for showing me this "trick"...!!!