√5t²-2t+2是怎么得出这个√5(t-1/5)²+9/5

√5t²-2t+2是怎么得出这个√5(t-1/5)²+9/5
√5t²-2t+2是怎么得出这个√5(t-1/5)²+9/5

√5t²-2t+2是怎么得出这个√5(t-1/5)²+9/5
明显答案有问题,配方可知：原式=√5(t^2-(2/√5)t+((1/√5)^2)-1/5)+2=√5(t-(1/√5))^2-
√5/5+2