1.已知a+1/a=6,求a^2+1/a^的值2.a^2+1/a^2=6,求a-1/a的值

Question

1.已知a+1/a=6,求a^2+1/a^的值 2.a^2+1/a^2=6,求a-1/a的值

Answer 1

1. a+1/a=6 两边同时平方得 a^2+1/a^+2=36 所以a^2+1/a^=34
2. (a-1/a)^2=a^2+1/a^2-2=6-2=4 所以 a-1/a=2 或a-1/a=-2 完毕!