先化简再求值:t/(t+1)-(t²-1)/【(t+2)²-1】*(t+3)/(t+1),其中t=(根号2)-1
问题描述:
先化简再求值:t/(t+1)-(t²-1)/【(t+2)²-1】*(t+3)/(t+1),其中t=(根号2)-1
答
t/(t+1)-(t²-1)/【(t+2)²-1】*(t+3)/(t+1)=t/(t+1-(t+1)(t-1)/(t+2+1)(t+2-1)x(t+3)/(t+1)=t/(t+1)-(t+1)(t-1)/(t+3)(t+1)x(t+3)/(t+1)=t/(t+1)-(t-1)/(t+1)=1/(t+1)=1/[(根号2)-1+1]=(根号2)/2