+0  
 
0
324
1
avatar+956 

If tanx = 6/8 what is cos2x that 0

 

Options: 

-8/5

8/5

-7/25

7/25 

 

I have 20 minutes so if you could be fast, I'd really really appreciate it :D

 Dec 13, 2017
 #1
avatar+94619 
+2

If tan x  =  6/8.....  this is a 6-8-10 right triangle......then cos x  =  8/10   ....so.....

 

cos 2x  = 2cos^2x  - 1

 

cos 2x  =  2(8/10)^2  -  1

 

cos2x =  2 (64/100)  -  1

 

cos2x  =  128/100  -  100/100 

 

cos 2x   =  28/100  =     7/25   

 

 

 

cool cool cool

 Dec 13, 2017

14 Online Users

avatar
avatar

New Privacy Policy

We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive information about your use of our website.
For more information: our cookie policy and privacy policy.