1. Prove that
2 tan x / 2- sec^2 x = tan 2x.

Answer:
Step-by-step explanation:
Use trig identities:
1
+
tan
2
x
=
1
cos
2
x
=
sec
2
x
(
1
−
tan
x
)
=
1
+
tan
2
x
−
2
tan
x
=
sec
2
x
−
2
tan
x