# Trig problems

1. Sep 19, 2012

### lionely

tan 2θ= -1

I don't understand how to work this question could someone walk me through it?

ranging between -180 and 180

Last edited: Sep 20, 2012
2. Sep 19, 2012

### Mentallic

For what value of x does $\tan(x)=-1$ ?

3. Sep 19, 2012

### lionely

I believe -45

4. Sep 20, 2012

### skiller

deleted

Last edited: Sep 20, 2012
5. Sep 20, 2012

### micromass

Staff Emeritus
Is that the only value??

6. Sep 20, 2012

### lionely

Yes what are the possible values of theta and I'm sure, I haven't started working in radians at school as yet... =/

7. Sep 20, 2012

### Mentallic

Ok so you know that there are infinitely many solutions to tan(x)=-1 right? Because just like how the sin and cos graphs go on forever, the tan function does as well. Anyway, are you expected to find all the solution for θ between -180o and 180o?

And another thing, if tan(-45o)=-1 and we have that 2θ=-45o then what is θ?

8. Sep 20, 2012

### lionely

Theta would be -22.5 oh and I forgot to mention the question asked between -180 and 180 sorry.