1. For the given function f(x, y), calculate the partial derivative with respect to x and y.

i. f(x, y) = 5x^4 - 3x²y³ + 7y^5

ii. f(x, y) = 3y³x²

iii. f(x, y) = 7x³ - 9xy + 2y^5

iv. f(x, y) = 3x