1+tanα/1-tanα=3+2根号2
1+tanα=3+2根号2-(3+2根号2)tanα
(4+2根号2)tanα=2+2根号2
tanα=(2+2根号2)/(4+2根号2)
tanα=根号2/2tanα=(2+2根号2)/(4+2根号2)怎样化成tanα=根号2/2tanα=(2+2根号2)/(4+2根号2)=(1+根号2)/(2+根号2)=[(1+根号2)(2-根号2)]/[(2+根号2)(2-根号2)]=(2-根号2+2根号2-2)/(4-2)=根号2/2