Question

2 tan(4x) / 1 - tan (4x) tan (4x) is equal to:

a) tan 2 x
b) tan 4 x
c) tan 8 x
d) tan x

Answer 1

you need this formula :
tan(a+b) = (tan(a) + tan(b))/(1-tan(a)(tan(b))

Answer 2

or even this would work directly :P

tan 2A = 2 tan A/ (1+ tan^2 A)

Answer 3

correction
it is \[\tan 2A=\frac{ 2\tan A }{1-\tan ^{2}A }\]

Answer 4

just typo from hartnn :P

Answer 5

I know only typing error.

Answer 6

thanks for correcting :)