Right square pyramid V=189cm³
I assume you're supposed to establish the identity,
cos(A) cos(2A) cos(4A) = 1/8 sin(8A) / sin(A)
Recall the double angle identity for sine:
sin(2<em>x</em>) = 2 sin(<em>x</em>) cos(<em>x</em>)
Then you have
sin(8A) = 2 sin(4A) cos(4A)
sin(8A) = 4 sin(2A) cos(2A) cos(4A)
sin(8A) = 8 sin(A) cos(A) cos(2A) cos(4A)
==> sin(8A)/(8 sin(A)) = cos(A) cos(2A) cos(4A)
as required.
You can use any letter but when you label it x you find x
<h3>Answer:</h3>
A. y = -1/3x + 2 . . . . . . . . assuming a typo in your problem statement
<h3>Explanation:</h3>
The point (0, 2) is the y-intercept. This tells you the equation will be something of the form ...
... y = mx + 2 . . . . . . matching only answer choices A and C
_____
Knowing this, you can either substitute the values x=3, y=1 into these two equations to see which one works (it is not C), or you can look at the two points and determine the value of the slope.
The slope is ...
... (difference in y)/(difference in x) = (1-2)/(3-0) = -1/3 . . . . . matches choice A
The equation of the line is ...
... y = -1/3x + 2 . . . . . matches answer choice A