题目已知a=2−3a=2-\sqrt{3}a=2−3.(1)(1)(1)求a2−4a+4a^{2}-4a+4a2−4a+4的值；(2)(2)(2)化简并求值:a2−1a+1−a2−2a+1a2−a\frac{{a^2}-1}{a+1}-\frac{\sqrt{{a^2}-2a+1}}{{a^2}-a}a+1a2−1−a2−aa2−2a+1.知识点：代数式求值、二次根式的性质与化简、二次根式的化简求值章节：未标注
