Question

If tan x = 1/7 then the value of cos 2x is​

Answer 1

Answer:

24/25

Step-by-step explanation:

tan x =1/7

$1 + tan^{2}A = sec^{2} A$

$1 + 1/49 = sec^{2}x$

$sec^{2} x = 50/49$      

sec x = 5√2 / 7

1/cos x= 5√2 / 7

cosx = 7/5√2

         

cos 2x =  $2cos^{2} x -1$

           =  2 ( 49/50) -1

           = 98/50 -1

           = 48 / 50

           = 24 / 25