Evaluate a2 + b for a= 1/2 and b= -1/2

Step-by-step explanation:

a^2 + b

(1/2)^2 - 1/2

1/4 - 1/2

1/4 - 2/4 = -1/4

b) the dogs need to shift their focus to human scent.

∠acb = 8°

step-by-step explanation:

∠xba lies on the circle and is half the measure of the intercepted arc ax

hence

measure of arc ax = 2 × 42° = 84°

∠acb is outside the circle and is

∠acb = (arcab - arcax ), hence

∠acb = 0.5 (100 - 84) = 0.5 × 16° = 8°