Question

solve 2tan15°tan45°tan75°

Answer 1

hope it helps you

2tan15*tan45*tan75=2tan

15*tan75 Since tan 45 ° =1 

tan 90°=tan(15°+75°)
=(tan15°+tan 75°)/(1−tan15°tan75°) 

Since tan 90° is undefined 

→(1−tan15°tan75°) =0 

or tan15°tan75° =1 

Hence 2tan15*tan45*tan75=2tan15*tan75 =2x1=2

that's all
hope helps

Answer 2

2tan15.tan75.tan45
2tan15.cot(90-75).1  [tan45=1]
2tan15.cot15.1
2.1.1=2 [tan.cot=1]