This problem was in PrepSwift’s Sequences 1 practice questions
I managed to solve this radical by brute-force with FOIL method. Are there any other way to do this quicker?
Calculator.
How would I input this in the GRE calculator? Because it would give me number in infinite decimal form. I can’t even input 1+ sqrt(5) because it would show NaN.
You should be able to input \sqrt{5} and add 1. The fact that the number is in decimal form is OK - remember the hint that the elements of the sequence are all integers.