若a+1\a=2,则a^2+1/a^2=＿＿ a^4+1/a^4=______

若a+1\a=2,则a^2+1/a^2=＿＿ a^4+1/a^4=______
若a+1\a=2,则a^2+1/a^2=＿＿ a^4+1/a^4=______

若a+1\a=2,则a^2+1/a^2=＿＿ a^4+1/a^4=______
两个答案都是2 用带入法,或者直接求方程.