来自董光弘的问题
1.若abc=1,求证:1/(ab+a+1)+1/(bc+b+1)+1/(ca+c+1)=12.已知:(a-b)/(b-c)=a/c,求证:1/a+1/c=2/b3.在△ABC中,∠B=30度,∠C=45度,求AB:BC:AC
1.若abc=1,求证:1/(ab+a+1)+1/(bc+b+1)+1/(ca+c+1)=1
2.已知:(a-b)/(b-c)=a/c,求证:1/a+1/c=2/b
3.在△ABC中,∠B=30度,∠C=45度,求AB:BC:AC
1回答
2020-12-2004:30