Paper 1, Section I, C

Vectors and Matrices
Part IA, 2020

Given a non-zero complex number z=x+iyz=x+i y, where xx and yy are real, find expressions for the real and imaginary parts of the following functions of zz in terms of xx and yy :

(i) eze^{z},

(ii) sinz\sin z

(iii) 1z1zˉ\frac{1}{z}-\frac{1}{\bar{z}},

(iv) z3z2zˉzzˉ2+zˉ3z^{3}-z^{2} \bar{z}-z \bar{z}^{2}+\bar{z}^{3},

where zˉ\bar{z} is the complex conjugate of zz.

Now assume x>0x>0 and find expressions for the real and imaginary parts of all solutions to

(v) w=logzw=\log z.