## aussy123 2 years ago Can someone explain this problem to me? tan(-20°) = -tan20° True- The answer is true, but I dont know why. False

1. harsimran_hs4

ok let`s try can you tell sin(-x) = ? (in terms of sin(x))

2. aussy123

umm Im not sure

3. harsimran_hs4

anyways try...tell whatever is in your mind

4. aussy123

sin(180 -) = sin

5. harsimran_hs4

ok so sin(-x) = - sin(x) (clear ?)

6. aussy123

okay

7. harsimran_hs4

now try for cos(-x) = ?

8. aussy123

okay cos(-x)=-cos(x)

9. harsimran_hs4

NO!!

10. aussy123

cos(-x)=cos(x)

11. harsimran_hs4

so now on right track so tan(-x) = sin(-x)/ cos(-x) = -sin(x)/ cos(x) = - tan(x) do you get it now?

12. aussy123

yes, I believe so

13. harsimran_hs4

why are you still not sure what`s the confusion?

14. aussy123

Im saying I believe so, because Im new to this so im not going to know this, but I believe I know enough to get through this lesson

15. harsimran_hs4

ok so does that end this question or there is still something that you need to ask?

16. aussy123

No Im good, Thank you for your time!

17. harsimran_hs4

:)