The unit circle or trigonometric circle is a circle whose center islocated at the origin of the Cartesian plane and its radius is 1(one). It is used in the study of trigonometric functions such assine, cosine and tangent. - Understand how the projections of thearcs sine, cosine and tangent work in the unit circle (ortrigonometric circle); - Why the values ​​of sine and cosine arelimited to -1 and +1; - Why the tangent of 90 ° and 270 ° are notdefined - When and where the values ​​of the trigonometric ratios(sine, cosine, tangent) are positive, negative, zero or null;-------------------------------------------------------------------------If you have any suggestion fell free to contact me. or If you getany error or problem running the app. Send me the report and somemessage. So I get more information about your android version,screen size, ... so I can fix it. Thanks.