SOLUTION: Which of the following contains a false solution to the equation sinθ cotθ-cos^2 θ=0? A. 90 degrees and 270 degrees B. 0 degrees and 180 degrees C. 0 degrees an

Algebra ->  Trigonometry-basics -> SOLUTION: Which of the following contains a false solution to the equation sinθ cotθ-cos^2 θ=0? A. 90 degrees and 270 degrees B. 0 degrees and 180 degrees C. 0 degrees an      Log On


   

Question 344829: Which of the following contains a false solution to the equation sinθ cotθ-cos^2 θ=0?
A. 90 degrees and 270 degrees
B. 0 degrees and 180 degrees
C. 0 degrees and 270 degrees
D. 90 degrees
Thank you, Thank you so much for your help!!!!!
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
Sin%28theta%29Cot%28theta%29-Cos%5E2theta=0

try A
A. 90 degrees and 270 degrees

Sin%28%2290%B0%22%29Cot%28%2290%B0%22%29-Cos%5E2%22%2890%B0%29%22=0
1%2A0-0%5E2=0
0=0

Sin%28%22270%B0%22%29Cot%28%22270%B0%22%29-Cos%5E2%22%28270%B0%29%22=0
-1%2A0-0%5E2=0
0=0

Those are true solutions.

Try B
B. 0 degrees and 180 degrees

Sin%28%220%B0%22%29Cot%28%220%B0%22%29-Cos%5E2%22%280%B0%29%22=0

Since Cot%28%220%B0%22%29 is undefined, B is a false solution.
No use to try 180°.

Try C
C. 0 degrees and 270 degrees

Sin%28%220%B0%22%29Cot%28%220%B0%22%29-Cos%5E2%22%280%B0%29%22=0

Since Cot%28%220%B0%22%29 is undefined, C is a false solution.
Even though 270° is a solution, as we saw in A, 0° is not.

Try D
D. 90 degrees

We saw in part A that 90° is a solution. 

B and C are the only ones which contain a false solution.

Edwin