What is \tan^2\alpha equal to ?

For the next two (02) items that follow : p\sin^2\alpha + q\cos^2\alpha = m and p\cos^2\beta + q\sin^2\beta = n

  1. A. \frac{m-q}{p-m}
  2. B. \frac{m-p}{q-m}
  3. C. \frac{m-q}{m-p}
  4. D. \frac{m-p}{m-q}

Correct Answer: A. \frac{m-q}{p-m}

Explanation

Rewrite q\cos^2\alpha as q(1 - \sin^2\alpha). The equation becomes p\sin^2\alpha + q - q\sin^2\alpha = m \implies \sin^2\alpha (p-q) = m-q \implies \sin^2\alpha = \frac{m-q}{p-q}. Then \cos^2\alpha = 1 - \sin^2\alpha = 1 - \frac{m-q}{p-q} = \frac{p-m}{p-q}. Therefore, \tan^2\alpha = \frac{\sin^2\alpha}{\cos^2\alpha} = \frac{m-q}{p-m}.

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