B=π-A-C
b^2=ac
根据正选定理得(sinB)^2=sinA sinC
conB=3/4
(sinB)^2=1-(cosB)^2=1-9/16=7/16
sinB=√7/4
cotA+cotC
=cosA/sinA+cosC/sinC
=(sinCcosA+cosCsianA)/sinAsinC
=sin(A+C)/(sinB)^2
=sin(π-B)/(sinB)^2
=sinB/(sinB)^2
=1/sinB
=4√7/7
******************************************************************************
如果觉得我回答的好,请采纳,谢谢
*****************************************************************************
温馨提示:答案为网友推荐,仅供参考