Answer:
0.619
Step-by-step explanation:
from the question we have the following data:
probability of motor 1 breaking = 65% = 0.65
probability of motor 2 breaking = 35% = 0.35
probability of motor 3 breaking = 5% = 0.05
since we have 3 motors the probability of any of them breaking down is = 
but what the question requires from us is the conditional probability of the first one being installed
we have to solve this questions using bayes theorem
such that:

= 
= 
= 0.618966
approximately 0.619
therefore the conditional probability ralph installed the first motor is 0.619
Answer: x = -1, 1
Step-by-step explanation:
x = r sin θ cos Ф
x² = r² sin² θ cos² Ф
y = r sin θ sin Ф
y² = r² sin² θ sin² Ф
z = r cos θ
z² = r² cos² θ
x² + y² + z²
= r² sin² θ cos² Ф + r² sin² θ sin² Ф + r² cos² θ
= r² sin² θ (cos² Ф + sin² Ф) + r² cos² θ
= r² sin² θ + r² cos² θ
= r² (sin² θ + cos² θ)
= r² √