## anonymous one year ago Find all solutions in the interval [0, 2π). 7 tan3x - 21 tan x = 0

1. anonymous

@Nnesha

2. Nnesha

same like last one let tan x =a then take out common factor

3. anonymous

4. Nnesha

ye... but first you should find out common factor

5. Nnesha

$\huge\rm 7a^3 -21 a = 0$ what is common factor ?

6. anonymous

7 is a common factor

7. Nnesha

yes right and what else ?

8. anonymous

7a(a^2-3)=0

9. Nnesha

yep right set both 7a and a^2 -3 equal to zero solve for a

10. anonymous

a=0 and a=sqrt.3

11. Nnesha

yep that means tan x = 0 and tanx = sqrt{3} unit circle!

12. Nnesha

tan = sin /cos

13. anonymous

so wait what would I look for

14. Nnesha

tanx = 0 and tan x =sqrt 3 this one z tricky you have to divide sin over cos to find out tan