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Find all angles 0 (theta) such that zero degree is less than or equal to theta and less than or equal to 360 degrees for which the statement sin (-104 degrees) = sin 0 theta is true

Find all angles 0 (theta) such that zero degree is less than or equal to theta and-example-1
Find all angles 0 (theta) such that zero degree is less than or equal to theta and-example-1
Find all angles 0 (theta) such that zero degree is less than or equal to theta and-example-2
Find all angles 0 (theta) such that zero degree is less than or equal to theta and-example-3
User Crandel
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1 Answer

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Step-by-step explanation

So basically we must find an angle between 0° and 360° that meets the following:


\sin(-104^(\circ))=\sin\theta

First of all it's important to recall a property of the sine:


\sin x=\sin(x+360^(\circ))

Then if we take x=-104° we get:


\sin(-104^(\circ))=\sin(-104^(\circ)+360^(\circ))=\sin256^(\circ)

So for now we know that 256° is one value of theta.

For all the angles between 0° and 360° there are always two angles that share the same sine. For any angle in the first quadrant (0° to 90°) there's another angle in the second quadrant (90° to 180°) that has the same sine. The same happens with the third (180° to 270°) and fourth quadrant (270° to 360°). 256° is in the third quadrant which means that there's another possible theta in the fourth quadrant. The difference between this angle and 270° must have the same absolute that the difference between 256° and 270°. Then for the new theta we have:


\begin{gathered} \lvert{270^(\circ)}-256^(\circ)\rvert=\lvert{\theta-270^(\circ)}\rvert \\ 14^(\circ)=\lvert{\theta-270^(\circ)}\rvert \end{gathered}

Since theta is part of the fourth quadrant is greater than 270° so the term inside the absolute value is positive and we can get rid of the module:


14^{\operatorname{\circ}}=\theta-270^(\circ)

Then we add 270° to both sides:


\begin{gathered} 14^{\operatorname{\circ}}+270^{\operatorname{\circ}}=\theta-270^{\operatorname{\circ}}+270^{\operatorname{\circ}} \\ \theta=284^(\circ) \end{gathered}Answer

Then the answers are 256° and 284°.

User Shakilur
by
8.3k points

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