The x-value of a midpoint is the average of the x-values of the ends.
The y-value of a midpoint is the average of the y-values of the ends.
The x-value of the end at b is 20 and it's 18 at the middle.
x has decreased by 2 in the course of 1/2 of the line.
So it will decrease another 2 during the other half of the line.
The x-value at the other end, at a, then, is 16.
The y-value of the end at b is 4 and it's -2 at the middle.
y has decreased by 6 in the course of 1/2 of the line.
So it will decrease another 6 during the other half of the line.
The y-value at the other end, at a, then, is -8.
The other end of the line, at a, is at (16, -8) .
The sum of the coordinates at a (p+q) is 8 .
We know that sin2x=2sinxcosx
(search the net for proof if you wish)
So the original equation becomes
2sinxcosx-sinx=0
The two terms both have sinx that can be taken out to get:
sinx(2cosx-1)=0
This is true if sinx=0 or 2cosx-1=0 , rewritten: cosx=1/2
sinx=0 than x=2kπ
cosx=1/2 than x=π/3+2kπ
where k is an integer
Answer would be 140 why does my answer need to be 20 words long ugh