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Please Help acellus is torture.

Please Help acellus is torture.-example-1
User Prasham
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1 Answer

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The angle made by the vector is
\theta such that


\tan(\theta) = (18.4\,\rm m)/(-28.7\,\rm m) \approx -0.6411

Before taking the inverse tangent of both sides, recall that
\arctan returns a number between -π/2 and π/2 radians, or -90° and +90°. The vector in the diagram clearly makes an angle between 90° and 180°, however, so we use the fact that tangent has a period of π rad / 180° to write


\theta \approx \arctan(-0.6411) + 180^\circ n

where
n\in\Bbb Z.

Now,


\arctan(-0.6411) \approx -0.5701 \,\mathrm{rad} \approx -32.6639^\circ

Add 180° to this to recover the correct angle.


\theta = \arctan(-0.6411) + 180^\circ \approx \boxed{147.34^\circ}

User Vanz
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