FP1 Topic 3: Complex numbers
Modulus and argument of complex numbers 2
If z = x+iy then |z| = \sqrt{x^2+y^2} and arg(z) = \tan^{-1}\displaystyle \frac{y}{x} The argument is given in radians in the range:-\pi \le arg(z) \le \pi When finding the argument you must make sure the angle is in the correct quadrant. This depends upon the signs of the real part x and the imaginary part y in the complex number.

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