Calculate Mirror Angle

Calculate Mirror Angle
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Hi I'm working on a project where I need to calculate what angle a mirror needs to be at in order to reflect a source of light onto a particular location on a surface. A lot like this: Help finding solution for trigonometric equation

Only without the stuff about cylinders.

Judging by this diagram how can I solve for $C$? Ivella states that $c = \frac{a+b}{2}$ but I don't see how? Should it be $c= \frac{b-a}{2}$ ?

That seems more likely, though I'm not sure about that either.

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1 Answer

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Since angle of incident$=$ angle of reflection We get $ a+c=b-c$ ..............$ 1$

Also from figure we get $\frac{\pi}{2}-(b-c)-c=\tan^{-1} \frac{y}{x}$ Gives $\frac{\pi}{2}-b= \tan^{-1} \frac{y}{x}$ This gives $b$ and we know $a$ as it is our incident ray angle,so from $1$ we get $ c$

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David Miller

David Miller brings 15 years of experience in global economics, personal finance strategy, and market dynamics. He specializes in turning complex economic trends into actionable insights for everyday readers.