Question

tan 15 ° tan 30 ° tan 45° tan 60 ° tan 75 °

Answer 1

By using tan(900−x)=cot(x)

Observe that tan750=tan(900−150)=cot(150)

And tan600=tan(900−300)=cot(300)

So we have

tan150⋅tan300⋅tan450⋅cot300⋅cot150=tan450=1