Question

Find the exact value of tan 2x if tan x = 7/11and PI is less than or equal to x which is less than or equal to 3pi/2

Answer 1

have you come across compound angle formulae yet?

Answer 2

I was probably supposed to... but no.

Answer 3

well there's a crude but quick way of doing this, or the compound angle way which is probably the official way

Answer 4

does this look familiar? :
\[\tan2x = \frac{2tanx}{1-2\tan^2{x}}\]

Answer 5

Yws.

Answer 6

ok, well substitute into that formula tanx = 7/11

Answer 7

tan2x = 2(7/11)/(1-2(49/121))

Answer 8

= (14/11)/(23/121)
=(14*121)/(23*11)

Answer 9

etc etc

Answer 10

I got it..

Answer 11

:D good good