Complex arithmetic in Java

Complex.java

public class Complex {
	private double real;
	private double imag;

	public Complex(final double real, final double imag) {
		this.real = real;
		this.imag = imag;
	}

	public double real() {
		return real;
	}

	public double imag() {
		return imag;
	}

	public Complex add(final Complex that) {
		return new Complex(this.real + that.real, this.imag + that.imag);
	}

	public Complex subtract(final Complex that) {
		return new Complex(this.real - that.real, this.imag - that.imag);
	}

	public Complex mult(final Complex that) {
		double real = this.real * that.real - this.imag * that.imag;
		double imag = this.real * that.imag + this.imag * that.real;
		return new Complex(real, imag);
	}

	public static double mod(final Complex z) {
		return Math.sqrt(z.real * z.real + z.imag * z.imag);
	}

	public Complex divide(final Complex that) {
		double real = this.real * that.real + this.imag * that.imag;
		double imag = this.imag * that.real - this.real * that.imag;
		double denom = mod(that);
		return new Complex(real / denom, imag / denom);
	}

	public Complex mult(final double scalar) {
		return new Complex(this.real * scalar, this.imag * scalar);	
	}

	public Complex divide(final double scalar) {
		return new Complex(this.real / scalar, this.imag / scalar);	
	}

	@Override
	public String toString() {
		return "Complex(" + this.real + ", " + this.imag + ")";
	}
}