12/11/20 00:13:17.88 .net
IJ={<tex>a_{1}b_{1}+a_{2}b_{2}+\dots+a_{n}b_{n}</tex>
<tex>x+y=\sum^{n}_{k=1}a_{k}b_{k}+\sum^{m}_{l=1}a_{l}b_{l}</tex>
12/11/20 00:13:17.88 .net
IJ={<tex>a_{1}b_{1}+a_{2}b_{2}+\dots+a_{n}b_{n}</tex>
<tex>x+y=\sum^{n}_{k=1}a_{k}b_{k}+\sum^{m}_{l=1}a_{l}b_{l}</tex>