I'm converting -3,4 to polar.
I have come up with r = +/ 5
And tan (x) = -4/3
When I do x = arctan (-4/3)
in my calculator I get -.927 but the book has 2.214
Why?
Thanks.
Have a look at this webpage. You will see the reply is correct.
The point $\displaystyle (-3,5)\in II$ and $\displaystyle {\frac{-\pi}{2}<\arctan \left( {\frac{{ - 4}}{3}} \right)}<0$ therefore adding $\displaystyle \pi$ gives the correct second quadrant angle.