Question

What is the distance between the following polar coordinates?: `(5,(7pi)/4), (3,(9pi)/8)`

Answer 1

`sqrt(34-30cos((5pi)/8))~~6.744`

Explanation:

`z=|5Cis((7pi)/4)-3Cis((9pi)/8)|`

=`sqrt((5cos((7pi)/4)-3cos((9pi)/8))^2+(5sin((7pi)/4)-3sin((9pi)/8))^2)`

=`sqrt(5^2+3^2-2*5*3*cos((7pi)/4-(9pi)/8))`

=`sqrt(34-30cos((5pi)/8))`

`~~6.744`