Question

如果a-b=5,ab=3/2,求a的2次方+b的2次方和(a+b)的2次方的值

Answer 1

^2表示平方

a-b=5

两边平方得

(a-b)^2=25

a^2-2ab+b^2=25

a^2+b^2=2ab+25

=3+25

=28

(2)

(a+b)^2

=a^2+2ab+b^2

=a^2+b^2+2ab

=28+3

=31