#quadratic-features

Question 1: Single choice

Eight training points $(x_1, x_2, x_3)$ with binary labels:

label 1	label 0
$(1, 1, -1)$	$(1, 1, 2)$
$(0, 2, -2)$	$(0, 2, 1)$
$(0, -1, 1)$	$(1, -1, -1)$
$(0, -2, 2)$	$(1, -2, -2)$

A quadratic logistic regression $g(w_0 + w_1 x_i + w_2 x_j + w_3 x_i x_j + w_4 x_i^2 + w_5 x_j^2)$ may use only one pair of features $(x_i, x_j)$ . Which pair gives the lowest training error?

$(x_2, x_3)$ 1
$(x_1, x_2)$ 2
$(x_1, x_3)$ 3
All three pairs reach zero training error4

Timed test