Question

prove that tan 100+tan 125 +tan100.tan125+1

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.

hope it helps.. regards