Answer:
Solution : Option C
Step-by-step explanation:
We have the equations r² = x² + y², x = r cos(θ), and y = r sin(θ) that can be used to solve this problem. In this case we only need the second two equations ( x = r cos(θ), and y = r sin(θ) ) as we don't need to apply the concept of circles etc here.
Given : x = - 9,
( Substitute r cos(θ) for x )
r cos(θ) = - 9,
r = - 9 / cos(θ)
( Remember that sec is the reciprocal of cos(θ). Substitute sec for 1 / cos(θ) )
r = - 9 sec(θ)
Therefore the third option is the correct solution.
Answer:
Reject H0
Step-by-step explanation:
Given :
H0: The frequencies are equal. H1: The frequencies are not equal
Category f0 A 10 B 30 C 30 D 10
Total f0 = (10 + 30 + 30 + 10) = 80
Expected frequency is the same for all categories :
Expected frequency = 1/4 * 80 = 20
χ² = Σ(observed - Expected)² / Expected
χ² = (10-20)^2 / 20 + (30-20)^2 /20 + (30-20)^2 / 20 + (10-20)^2 / 20
χ² = (5 + 5 + 5 + 5) = 20
Pvalue = 0.00017
Pvalue < α
1. -.6 or -3/5
2. -.4 or -4/9
The measure of ∠BEC would be 80 degrees
