## anonymous 5 years ago Solve this equation on the interval 0 θ < 2π. If there is only one solution, write it in the first box and write NONE in the second box. If there is no solution, write NONE in both boxes. Round your answer(s) to two decimal places using radians. -2 cos(θ) + 1 = 2 θ = (smaller value of θ) θ = (larger value of θ)

1. anonymous

the interval is 0( which is less than or equal to) theta ( which is less than) 2pi

2. anonymous

-2cos(x) = 1 cos(x) = -1/2 the related angle is cos inverse of 1/2 , which is 60 degrees

3. anonymous

cos is negative in the 2 and 3 quadrants

4. anonymous

x= 180 -60 and x= 180 + 60 x= 120 , 240 degrees

5. anonymous

$\frac{2\pi}{3} , \frac{4\pi}{3}$ in radians

6. anonymous

thanks. but the answer seems to be wrong? not sure why

7. anonymous

I am fairly sure what I did was correct

8. anonymous

could it be because the question says round the answer to two decimal points in radians?

9. anonymous

yes lol :|

10. anonymous

obviously if you entered the exact values then they wouldnt like it

11. anonymous

I assumed you would know how to convert the exact values into radians, lol, just calculator work

12. anonymous

yes, however i dont have a calc lol! i think the first one is 2(3.14)/3 ?

13. anonymous

http://www.wolframalpha.com/input/?i=cos%28x%29+%3D-1%2F2+%2C+0%3Cx%3C360 theres a calculator even solves eqns and integrals and everything

14. anonymous

I use it to check my answers

15. anonymous

ok thanks. but to be 100% sure(kind of forgot) radians is using pi as 3.14?

16. anonymous

yes approx that ,

17. anonymous

thanks mate. got it right!

18. anonymous

would you also be able to show me how to do the question just above this question?