The first picture represents the elements in B that are not (also) in A. So, we want the set difference of B and A:
For the second picture, we can work like this: if we take all the elements belonging to A, we only need to add the bottom-right part, which is the intersection of B and C. So, we can express the blue part as
Answer:
66.42°
Step-by-step explanation:
<u>Given:</u>
A(5, 3t+2, 2)
B(1, 3t, 2)
C(1, 4t, 3)
BA • BC = 4
Step 1: Find t.
First we have to find vectors BA and BC. We do that by subtracting the coordinates of the initial point from the coordinates of the terminal point.
In vector BA B is the initial point and A is the terminal point.
BA = OA - OB = (5-1, 3t+2-3t, 2-2) = (4, 2, 0)
BC = OC - OB = (1-1, 4t-3t, 3-2) = (0, t, 1)
Now we can find t because we know that BA • BC = 4
BA • BC = 4
To find dot product we calculate the sum of the produts of the corresponding components.
BA • BC = (4)(0) + (2)(t) + (0)(1)
4 = (4)(0) + (2)(t) + (0)(1)
4 = 0 + 2t + 0
4 = 2t
2 = t
t = 2
Now we know that:
BA = (4, 2, 0)
BC = (0, 2, 1)
Step 2: Find the angle ∠ABC.
Dot product: a • b = |a| |b| cos(angle)
BA • BC = 4
|BA| |BC| cos(angle) = 4
To get magnitudes we square each compoment of the vector and sum them together. Then square root.
Rounded to two decimal places:
Answer:
y = - x + 2
Step-by-step explanation:
The equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
y = 3x - 3 ← is in slope- intercept form
with slope m = 3
Given a line with slope m then the slope of a line perpendicular to it is
= -
= -
, hence
y = - x + c ← is the partial equation of the perpendicular line
To find c substitute (3, 1) into the partial equation
1 = - 1 + c ⇒ c = 1 + 1 = 2
y = - x + 2 ← equation of perpendicular line