Balmer, a Swiss middle school teacher, has successfully extracted spectral data from 9 / 5, 16 / 12, 25 / 21, () 49 / 45, 94 / 60, 81 / 77 What's in the middle What is the law

Balmer, a Swiss middle school teacher, has successfully extracted spectral data from 9 / 5, 16 / 12, 25 / 21, () 49 / 45, 94 / 60, 81 / 77 What's in the middle What is the law

Add 36 / 32
The rule is: in front of: the square of 3, the square of 4, the square of 5
Later: 5 + 7 = 12 12 + 9 = 21 21 + 11 = 32 32 + 13 = 45

What's the next data for spectral data, 9 / 5, 16 / 12, 25 / 21, 36 / 32?
I know the law of denominator, 12-5 equals 7, 21-12 equals 9, 32-21 equals 11, which in turn added 2, but I can't figure out the law of molecule. Please explain in detail ~ thank you!

Forty nine out of forty-five, the numerator is the denominator plus four

What's the seventh number

81 / 77 you seem to have written the wrong question. The first two numbers should be 9 / 5 and 16 / 12

Observe a group of fractions given, 8 out of 5, 16 out of 12, 25 out of 21, 36 out of 32,... Then the nth fraction can be expressed as

The denominator 5 12 21 32 is 2 ^ 2 + 1 3 ^ 2 + 3 4 ^ 2 + 5 5 ^ 2 + 7, and the nth term is: (n + 1) ^ 2 + (2 * n - 1)
The molecules didn't work out