1. C. Upper Left
2. B. For about 90% of their lifetime
Refer to the diagram shown below.
We want to find y in terms of d, φ and θ.
By definition,

Therefore
y = x tan(θ) (1)
y = (x - d) tan(φ) (2)
Equate (1) and (2).
![(x - d) \, tan(\phi) = x \, tan(\theta) \\ x[tan(\phi) - tan(\theta)] = d \, tan(\phi) \\ x= \frac{d tan(\phi)}{tan(\phi)-tan(\theta)}](https://tex.z-dn.net/?f=%28x%20-%20d%29%20%5C%2C%20tan%28%5Cphi%29%20%3D%20x%20%5C%2C%20tan%28%5Ctheta%29%20%5C%5C%20x%5Btan%28%5Cphi%29%20-%20tan%28%5Ctheta%29%5D%20%3D%20d%20%5C%2C%20tan%28%5Cphi%29%20%5C%5C%20x%3D%20%5Cfrac%7Bd%20tan%28%5Cphi%29%7D%7Btan%28%5Cphi%29-tan%28%5Ctheta%29%7D%20)
From (1), obtain the required expression for y.
Answer:
Answer:
Explanation: please see attached file I attached the answer to your question.