SOLUTION: Two stations due south of a leaning tower which leans towards north are at distance a and b from its foot. If x and y are the elevation of the top of the tower from these stat

Algebra ->  Trigonometry-basics -> SOLUTION: Two stations due south of a leaning tower which leans towards north are at distance a and b from its foot. If x and y are the elevation of the top of the tower from these stat      Log On


   



Question 1088961: Two stations due south of a leaning tower which leans towards north
are at distance a and b from its foot. If x and y are the elevation
of the top of the tower from these stations . Prove that its angle of
inclination z to the horizontal is given by cotz = (bcotx - acoty) / (b-a)

Answer by Edwin McCravy(20064) About Me  (Show Source):
You can put this solution on YOUR website!


The drawing below has NORTH to the right and SOUTH to the left.



We look at the triangles separately
Triangle PQS:

matrix%283%2C1%2C%22%3CP%22%2Bx=z%2Cso%2C%22%3CP%22=z-x%29%29     


Similarly for triangle PRS

 

We set the two expressions for PS equal to each other:

%28a%2Asin%28x%29%29%2Fsin%28z-x%29%22%22=%22%22%28b%2Asin%28y%29%29%2Fsin%28z-y%29

%28a%5E%22%22%2Asin%28x%29%29%2Asin%28z-y%29%22%22=%22%22%28b%5E%22%22%2Asin%28y%29%29%2Asin%28z-x%29

%28a%5E%22%22%2Asin%28x%29%29%2A%28sin%28z%29cos%28y%29-cos%28z%29sin%28y%29%5E%22%22%29%29%22%22=%22%22%28b%5E%22%22%2Asin%28y%29%29%2A%28sin%28z%29cos%28x%29-cos%28z%29sin%28x%29%5E%22%22%29

a%2Asin%28x%29sin%28z%29cos%28y%29-a%2Asin%28x%29cos%28z%29sin%28y%29%22%22=%22%22b%2Asin%28y%29sin%28z%29cos%28x%29-b%2Asin%28y%29cos%28z%29sin%28x%29

b%2Asin%28y%29cos%28z%29sin%28x%29-a%2Asin%28x%29cos%28z%29sin%28y%29%22%22=%22%22b%2Asin%28y%29sin%28z%29cos%28x%29-a%2Asin%28x%29sin%28z%29cos%28y%29

sin%28y%29cos%28z%29sin%28x%29%28b-a%29%22%22=%22%22b%2Asin%28y%29sin%28z%29cos%28x%29-a%2Asin%28x%29sin%28z%29cos%28y%29

Divide both sides by sin(x)sin(y)sin(z)

%28sin%28y%29cos%28z%29sin%28x%29%28b-a%29%29%2F%28sin%28x%29sin%28y%29sin%28z%29%29%22%22=%22%22

%22%22=%22%22

%28b-a%29%2A%28cos%28z%29%2Fsin%28z%29%29%22%22=%22%22b%28cos%28x%29%2Fsin%28x%29%29-a%28cos%28y%29%2Fsin%28y%29%29

%28b-a%29%2Acot%28z%29%22%22=%22%22b%2Acot%28x%29-a%2Acot%28y%29

Divide both sides by b-a

cot%28z%29%22%22=%22%22%28b%2Acot%28x%29-a%2Acot%28y%29%29%2F%28b-a%29

Edwin