Explanation:
To convert equations from polar form to rectangular form, we can use the following conversions:
1. For the equation r = tan(θ):
 In rectangular form, we can express r in terms of x and y using the relationships:
 r = √(x² + y²)
 tan(θ) = y / x
 Substituting these values into the equation r = tan(θ), we get:
 √(x² + y²) = y / x
 Squaring both sides of the equation, we have:
 x² + y² = y² / x²
 Multiplying both sides by x², we get:
 x⁴ + x²y² = y²
 Therefore, the rectangular form of the equation r = tan(θ) is:
 x⁴ + x²y² - y² = 0
2. For the equation r = 2 / (1 - sin(θ)):
 Using the same conversions as above, we have:
 r = √(x² + y²)
 1 - sin(θ) = 1 - y / r
 Substituting these values into the equation r = 2 / (1 - sin(θ)), we get:
 √(x² + y²) = 2 / (1 - y / √(x² + y²))
 Squaring both sides of the equation, we have:
 x² + y² = 4 / (1 - y / √(x² + y²))
 Multiplying both sides by (1 - y / √(x² + y²)), we get:
 (x² + y²)(1 - y / √(x² + y²)) = 4
 Expanding and simplifying the equation, we have:
 x² + y² - y = 4 - 4y / √(x² + y²)
 Multiplying both sides by √(x² + y²), we get:
 (x² + y² - y)√(x² + y²) = 4√(x² + y²) - 4y
 Therefore, the rectangular form of the equation r = 2 / (1 - sin(θ)) is:
 (x² + y² - y)√(x² + y²) = 4√(x² + y²) - 4y