First we use sin(a+b)= sinacosb+sinbcosa
and cos(a+b)=cosa cosb -sinasinb
tan(x+pi/2)= sin(x+pi/2) / cos(x+pi/2)
and sin(x+pi/2) = sinxcospi/2 + sinpi/2cosx =cosx,
<span>cos(x+pi/2) = cosxcospi/2- sinxsinpi/2= - sinx,
</span> because <span>cospi/2 =0, </span>and <span>sinpi/2=1
</span><span>=tan(x+pi/2)= sin(x+pi/2) / cos(x+pi/2)= cosx / -sinx = -1/tanx = -cotx
</span>from where <span>tan(x+pi/2)=-cotx</span>
Answer:
- translate down 3
- reflect across the horizontal line through A
Step-by-step explanation:
1. There are many transformations that will map a line to a parallel line. Translation either horizontally or vertically will do it. Reflection across a line halfway between them will do it, as will rotation 180° about any point on that midline.
In the first attachment, we have elected to translate the line down 3 units.
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2. Again, there are many transformations that could be used. Easiest is one that has point A as an invariant point, such as rotation CW or CCW about A, or reflection horizontally or vertically across a line through A.
Any center of rotation on a horizontal or vertical line through A can also be used for a rotation that maps one line to the other.
In the second attachment, we have elected to reflect the line across a horizontal line through A.
Alice receives 9 out of the 24 pens.