由tanα=
,1 2
(1)
=2sinα?3cosα 2sinα+cosα
=2tanα?3 2tanα+1
=-1;2×
?31 2 2×
+11 2
(2)4sin2α+2sinα?cosα-1
=
4sin2α+2sinα?cosα?sin2α?cos2α
sin2α+cos2α
=
3sin2α+2sinα?cosα?cos2α
sin2α+cos2α
=
3tan2α+2tanα?1
tan2α+1
=
3×(
)2+2×1 2
?11 2 (
)2+11 2
=
.3 5