bonsoir

√4 + √ 1 = 4 - 1

2 + 1 = 4 - 1

3 = 3

√9 + √4   = 9 - 4

3 + 2 =  5

5 = 5

√16 + √9 = 16 - 9

4 + 3 = 7

7 = 7

√ ( n + 1)² + √n² = ( n + 1 )² - n ²

( n + 1 ) + n  = ( n + 1 )² - n²  = ( n + 1 - n ) ( n + 1 + n )

2  n + 1 =    2 n + 1