tan(a+ ∏/4)=2
(1+tg a)/(1-tg a) = 2
tg a=1/3
所以
cos2a+3Sin²a+tan2a
=1+Sin²a + tan2a
Sin²a = 1/10
tan2a = 3/4
所以
cos2a+3Sin²a+tan2a
= 1+1/10+3/4=37/20
tan(a+ ∏/4)=2
(1+tg a)/(1-tg a) = 2
tg a=1/3
所以
cos2a+3Sin²a+tan2a
=1+Sin²a + tan2a
Sin²a = 1/10
tan2a = 3/4
所以
cos2a+3Sin²a+tan2a
= 1+1/10+3/4=37/20