1 + 1 * 2 + 2 = (9) = (3) 2 + 2 * 3 + 3 = (49) = (7) it's an algebraic expression that you find the law of these expressions 1 + 1 * 2 + 2 = () = () 2 + 2 * 3 + 3 = () = () 3 + 3 * 4 + 4 = () = () 4 + 4 * 5 + 5 = () = ()

1 + 1 * 2 + 2 = (9) = (3) 2 + 2 * 3 + 3 = (49) = (7) it's an algebraic expression that you find the law of these expressions 1 + 1 * 2 + 2 = () = () 2 + 2 * 3 + 3 = () = () 3 + 3 * 4 + 4 = () = () 4 + 4 * 5 + 5 = () = ()

1+1*2+2=（9 ）=（3 ） 2+2*3+3=（49 ）=（7 ） 3+3*4+4=（169 ）=（ 13） 4+4*5+5=（441 ）=（21 ） n+n（n+1）+（n+1）=[n（n+1）+1]

(1) Compare the following formulas. (2) through observation and induction, write a general conclusion that can reflect this law
Square of 4 + square of 3_____ 2 * 4 * 3, (- 2) square + 1 square______ 2*(-2)*1
Square of (radical 2) + square of (1 / radical 2)______ 2 * radical 2 * 1 / radical 2
Square of (root 3) + square of (root 3)______ 2 * radical 3 * radical 3

(a - b)² ≥ 0
Then a & sup2; + B & sup2; - 2Ab ≥ 0
That is a & sup2; + B & sup2; ≥ 2Ab

Observation formula: 1 = 1 square, 1 + 3 = 4 = 2 square, 1 + 3 + 5 = 9 = 3 square This law is expressed by algebraic expression (n is a positive integer) 1 + 3 + 5 + 7 + 9 + ＋（2n－1）＝（　　　）
emergency

Square of ((2n-1) + 1) / 2 = square of n