+0  
 
0
54
2
avatar

What are the solutions to the equation on [0,2pi)?

 

sec (3x) = -2sqrt3/3

 Mar 27, 2020
 #1
avatar+111330 
+1

sec (3x)  =    -2√3 / 3   =   -2 / √3

 

Note  that if this is the  sec(3x)  then  cos (3x)   must be    - √3/2

 

But  cos (x)  =  - √3/2      at        5pi/6,     7pi/6 ,  17pi/6, 19pi/6,  29pi/ 6, 31pi/ 6

 

Dividing each  by  3  we  get  the solutions

 

5pi/18, 7pi/18, 17pi/ 18 , 19pi/18, 29pi/ 18, 31pi/ 18

 

 

cool cool cool

 Mar 27, 2020
 #2
avatar+1970 
-1

Nice, Chris!

CalTheGreat  Mar 27, 2020

4 Online Users

avatar