Finite or infinite?
1) The set of all complex numbers a + bi such that a^2 + b^2 =1
2) x is an element of real numbers such that x^2 + 1 = 0.
c) {1, 3, 5} x {2, 4, 6, 8}
Explanations would be most helpful!

Question

Finite or infinite?
1) The set of all complex numbers a + bi such that a^2 + b^2 =1
2) x is an element of real numbers such that x^2 + 1 = 0.
c) {1, 3, 5} x {2, 4, 6, 8}
Explanations would be most helpful!

anonymous · Answer

@jonessodagirl73

anonymous · Answer

1) Geometrically the equation a^2+b^2=1 represents a circle in the argand plane, So a+bi represents points on the circumference of the circle, which is infinite,

anonymous · Answer

2) the equation x^2+1=0 has no solution for any real value of x, So total number of solutions =0, which is finite.

anonymous · Answer

3){1, 3, 5} x {2, 4, 6, 8}={(1,2),(1,4),(1,6),(1,8),(3,2),(3,4),(3,6),(3,8),(5,2),(5,4),(5,6),(5,8)}=12 elements which is finite.