Answer:
a) x = 1225.68
b) x = 1081.76
c) 1109.28 < x < 1198.72
Step-by-step explanation:
Given:
- Th random variable X for steer weight follows a normal distribution:
X~ N( 1154 , 86 )
Find:
a) the highest 10% of the weights?
b) the lowest 20% of the weights?
c) the middle 40% of the weights?
Solution:
a)
We will compute the corresponding Z-value for highest cut off 10%:
Z @ 0.10 = 1.28
Z = (x-u) / sd
Where,
u: Mean of the distribution.
s.d: Standard deviation of the distribution.
1.28 = (x - 1154) / 86
x = 1.28*86 + 1154
x = 1225.68
b)
We will compute the corresponding Z-value for lowest cut off 20%:
-Z @ 0.20 = -0.84
Z = (x-u) / sd
-0.84 = (x - 1154) / 86
x = -0.84*86 + 1154
x = 1081.76
c)
We will compute the corresponding Z-value for middle cut off 40%:
Z @ 0.3 = -0.52
Z @ 0.7 = 0.52
[email protected] < x < [email protected]
-.52*86 + 1154 < x < 0.52*86 + 1154
1109.28 < x < 1198.72
Answer:
2 - 
Step-by-step explanation:
Using the addition formula for tangent
tan(A - B) =
and the exact values
tan45° = 1 , tan60° =
, then
tan15° = tan(60 - 45)°
tan(60 - 45)°
= 
=
Rationalise the denominator by multiplying numerator/ denominator by the conjugate of the denominator.
The conjugate of 1 +
is 1 -
=
← expand numerator/denominator using FOIL
= 
= 
=
+ 
= 2 - 
Answer: ![(-9, 16]](https://tex.z-dn.net/?f=%28-9%2C%2016%5D)
This is the interval from -9 to 16. Exclude -9 but include 16.
=====================================================
Work Shown:
The idea is to multiply all sides by 5, then add 1 to all sides





This converts to the interval notation ![(-9, 16]](https://tex.z-dn.net/?f=%28-9%2C%2016%5D)
note: a curved parenthesis means "do not include this value in the solution set"; while a square bracket has us include the value. So we exclude -9 and include 16.