Answer:
see explanation
Step-by-step explanation:
Using the sum/ difference → product formula
cos x - cos y = - 2sin( 
)sin (
)
sin x - sin y = 2cos ( )sin ( )
Given
(cosA - cosB)² + (sinA - sinB )²
= [ - 2sin(
)sin(
) ]² + [ 2cos( )sin( ) ]²
= 4sin² ( )sin² ( ) + 4cos² ( )sin² ( )
= 4sin² ( )[ sin² ( ) + cos² ( ) ← sin²x + cos²x = 1
= 4sin² ( ) × 1
= 4sin² ( ) = right side ⇒ proven
It is multiplied by to because the raidouis is double.
Answer:
(a) x = -2y
(c) 3x - 2y = 0
Step-by-step explanation:
You can tell if an equation is a direct variation equation if it can be written in the format y = kx.
Note that there is no addition and subtraction in this equation.
Let's put these equations in the form y = kx.
(a) x = -2y
- y = x/-2 → y = -1/2x
- This is equivalent to multiplying x by -1/2, so this is an example of direct variation.
(b) x + 2y = 12
- 2y = 12 - x
- y = 6 - 1/2x
- This is not in the form y = kx since we are adding 6 to -1/2x. Therefore, this is <u>NOT</u> an example of direct variation.
(c) 3x - 2y = 0
- -2y = -3x
- y = 3/2x
- This follows the format of y = kx, so it is an example of direct variation.
(d) 5x² + y = 0
- y = -5x²
- This is not in the form of y = kx, so it is <u>NOT</u> an example of direct variation.
(e) y = 0.3x + 1.6
- 1.6 is being added to 0.3x, so it is <u>NOT</u> an example of direct variation.
(f) y - 2 = x
- y = x + 2
- 2 is being added to x, so it is <u>NOT</u> an example of direct variation.
The following equations are examples of direct variation:
X in this equation is about 4 and a half i know because i used a cacisnatter
