Question

Question #07bcc

Answer 1

Substitute `rcos(theta)" for "x and rsin(theta)" for "y`, then write r as a function of `theta`.

Explanation:

Substitute `rcos(theta)" for "x and rsin(theta)" for "y`:

`5rcos(theta) - 4rsin(theta) = -7`

Remove the common factor r:

`r(5cos(theta) - 4sin(theta)) = -7`

Divide both sides by `5cos(theta)-4sin(theta)`:

`r = (-7)/(5cos(theta) - 4sin(theta))`

Multiply numerator and denominator by -1:

`r = 7/(4sin(theta)-5cos(theta))`