Question

Tan100+tan125+tan100.tan125

Answer 1

tan225=tan(125+100), tan(180+45)= (tan125+tan100)/(1-tan125tan100) tan45= (tan125+tan100)/(1-tan125tan100), 1=(tan125+tan100)/(1-tan125tan100), tan125+tan100=1-tan125tan100, tan125+tan100+tan125tan100=1