If z=4+i, what is 1/z? (in the form a+bi)

1/z =1/(4+i) Multiply both top and bottom by the complex conjugate, z* = 4 - i, 1/z = (4-i)/((4+i)(4-i)) = (4-i)/(16+4i-4i-i2) = (4-i)/17 ans: 4/17 - i/17

Related Further Mathematics GCSE answers

All answers ▸

The circle c has equation x^2+ y ^2=1 . The line l has gradient 3 and intercepts the y axis at the point (0, 1). c and l intersect at two points. Find the co-ordinates of these points.


Consider the Matrix M (below). Find the determiannt of the matrix M by using; (a) cofactor expansion along the first row, (b) cofactor expansion along the second column


Use differentiation to show the function f(x)=2x^3–12x^2+25x–11 is an increasing function for all values of x


Find the coordinates of the stationary points on the curve y=x^5 -15x^3


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo
Cookie Preferences