Question

What is the Cartesian form of `( -1 , ( 9pi)/4 )`?

Answer 1

`(-sqrt2/2,-sqrt2/2)`

Explanation:

`x=rcos theta, y=rsin theta`

`r=-1,theta=(9pi)/4`

`x=-1cos((9pi)/4)=-sqrt2/2`

`y=-sin ((9pi)/4) = -sqrt2/2`

`(-sqrt2/2,-sqrt2/2)`