#ed_op#P#ed_cl#
亞斯 寫到:sinA+cosA>1#ed_op#BR#ed_cl#sinB+sinC=2sin[(B+C)/2]cos[(B-C)/2]=2cos(A/2)cos[(B-C)/2]#ed_op#BR#ed_cl#1+cosA=2cos(A/2)cos(A/2)#ed_op#BR#ed_cl#B<90<A+C#ed_op#BR#ed_cl#B-C<A#ed_op#BR#ed_cl#cos[(B-C)/2]>cos(A/2)#ed_op#BR#ed_cl#so sinB+sinC>1+cosA#ed_op#BR#ed_cl#sinA+sinB+sinC>1+cosA+sinA>2
#ed_op#/P#ed_cl##ed_op#P#ed_cl# #ed_op#/P#ed_cl##ed_op#P#ed_cl#命題有誤#ed_op#/P#ed_cl##ed_op#P#ed_cl#A=90度,B=60度,C=30度#ed_op#/P#ed_cl##ed_op#P#ed_cl#sinA+sinB+sinC=1+(1+√3)/2>2#ed_op#/P#ed_cl##ed_op#P#ed_cl#但不是銳角三角形#ed_op#/P#ed_cl##ed_op#P#ed_cl# #ed_op#/P#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl#