Question

If tanA = 1/5 find tan2A

Answer 1

tan2A =
`(5)/(12)`

Explanation:

Using the trigonometric identity

tan2A =
`(2tanA)/(1-tan^2A)`, thus

tan2A =
`(2((1)/(5)) )/(1-((1)/(5))^2 )`

=
`((2)/(5) )/(1-(1)/(25) )`

=
`((2)/(5) )/((24)/(25) )`

=
`(2)/(5)` ×
`(25)/(24)` =
`(5)/(12)`