Question

Resolva a equação An,2+ An-1,2 = 32 ​

Answer 1

An,2+ An-1,2 = 32

n(n-1) + (n-1)(n-2) = 32

n²-n + n²-3n+2 - 32 = 0

2n² -4n -30 = 0 ===> :(2)

n² - 2n -15= 0

∆= (-2)² -4.1.(-15)= 4 +60= 64 => √∆=8

n' = -b+√∆/2a= 2+8/2= 10/2= 5 ✓