Solution:
So, we have 2+41+42+41+⋯, which at first looks rather scary. But we notice a pattern! Because the nested fractions descend forever, the fraction essentially contains itself! So let a equal this fraction:
a=2+41+42+41+⋯
Thus,
a=2+41+4a
So now, we simply need to solve for a.
a=2+41+4a=2+44+aa=2+4a4+a=8+2a+4a4+a=8+6a4+a
Getting rid of the fraction by multiplying y 4+a, we get
4a+a2=8+6a⟹a2−2a−8=0
So now we factor...
a2−4a+2a−8=0
a(a−4)+2(a−4)=0
(a+2)(a−4)=0
So a can be −2 or 4. Since we know, by looking at the fraction, that a must be positive, a, and the value of the fraction, must be 4.
Tell me if you have any questions,

