According to this <em>trigonometric function</em>, −C gives you the OPPOSITE terms of what they really are, so be EXTREMELY CAREFUL.
Extended Information on the trigonometric function
NOTE: Sometimes, your <em>vertical</em><em> </em><em>shift</em><em> </em>might tell you to extend the troughs on each end of your graphs, beyond the <em>midline</em>.
* All tangent functions have NO AMPLITUDES.
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