解:
sinα+cosα=√2
(sinα+cosα)²=2
sin²α+cos²α+2sinαcosα=2
1+2sinαcosα=2
sinαcosα=½
(sinα-cosα)²
=sin²α+cos²α-2sinαcosα
=1-2·½
=0
sinα-cosα=0
(1)
sin²α-cos²α
=(sinα-cosα)(sinα+cosα)
=0·√2
=0
(2)
tanα+ 1/tanα
=sinα/cosα+ cosα/sinα
=(sin²α+cos²α)/(sinαcosα)
=1/½
=2