we know that cotA= and similarly cotB,cotC..by considering that cotA,cotB,cotC are inAP,we get2(c2+a2-b2)=(b2+c2-a2)+(b2+a2-c2),by simplifying,we get2b2=a2+c2,a2,b2,c2 are in AP
In triangle ABC,a2+c2=2002b2, then cotA + cotCcotB is equal to