Respuesta :
					                   As we all know,
According to the trigonometric identity,
tan70=tan(20+50)
tan70=(tan20+tan50)/1-tan20tan50
tan70-tan20tan50tan70=tan20+tan50
Also tan70tan20=tan70cot70=1
Hence
tan70-tan50=tan20+tan50
So tan70=tan20+2tan50
Hope this helps :) :)
					                
					             According to the trigonometric identity,
tan70=tan(20+50)
tan70=(tan20+tan50)/1-tan20tan50
tan70-tan20tan50tan70=tan20+tan50
Also tan70tan20=tan70cot70=1
Hence
tan70-tan50=tan20+tan50
So tan70=tan20+2tan50
Hope this helps :) :)
					                   tan(70-20)=tan50
tan70-tan20/1+tan20 tan70=tan50
tan20 tan70=cot70 tan70=1
tan70-tan20/2=tan50
tan70-tan20=2tan50
tan70=tan20+2tan50
					                
					             tan70-tan20/1+tan20 tan70=tan50
tan20 tan70=cot70 tan70=1
tan70-tan20/2=tan50
tan70-tan20=2tan50
tan70=tan20+2tan50
 
					                  