Answer:
<em>71.6 degrees </em>
Step-by-step explanation:
The formula for calculating the angle between two vectors is expressed as;
u.v = |u||v|cos theta
u.v = (8, 4).(9, -9)
u.v = 8(9)+4(-9)
u.v = 72-36
u.v = 36
|u| = √8²+4²
|u| = √64+16
|u| = √80
|v| = √9²+(-9)²
|v| = √81+81
|v| = √162
36 = √80*√162 cos theta
36 = √12960 cos theta
36 = 113.84 cos theta
cos theta = 36/113.84
cos theta = 36/113.84
cos theta = 0.3162
theta = arccos (0.3162)
<em>theta = 71.6 degrees </em>
<em>Hence the angle between the given vectors is 71.6 degrees </em>
Answer:
Step-by-step explanation:
304.5
Answer:
x= 15/2 im pretty sure
Step-by-step explanation:
Answer:
A certain company makes 12-volt car batteries. After many years of product testing, the company knows that the average life of a battery is normally distributed, with a mean of 50 months and a standard deviation of 9 months. If the company does not want to make refunds for more than 10% of its batteries under the full-refund guarantee policy, for how long should the company guarantee the batteries?
The company should guarantee the batteries for 38 months.
Step-by-step explanation:
Using standard normal table,
P(Z < z) = 10%
=(Z < z) = 0.10
= P(Z <- 1.28 ) = 0.10
z = -1.28
Using z-score formula
x = zσ + μ
x = -1.28 *9+50
x = 38
Therefore, the company should guarantee the batteries for 38 months.
