Unit circle with Triangle, marked angle <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \alpha }"><semantics><mrow class="MJX-TeXAtom-ORD"><mstyle displaystyle="true" scriptlevel="0"><mi>α<!-- α --></mi></mstyle></mrow><annotation encoding="application/x-tex">{\displaystyle \alpha }</annotation></semantics></math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b79333175c8b3f0840bfb4ec41b8072c83ea88d3" class="mwe-math-fallback-image-inline" aria-hidden="true" style="vertical-align: -0.338ex; width:1.488ex; height:1.676ex;" alt="\alpha "></span> and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \sin(\alpha )}"><semantics><mrow class="MJX-TeXAtom-ORD"><mstyle displaystyle="true" scriptlevel="0"><mi>sin</mi><mo>⁡<!-- ⁡ --></mo><mo stretchy="false">(</mo><mi>α<!-- α --></mi><mo stretchy="false">)</mo></mstyle></mrow><annotation encoding="application/x-tex">{\displaystyle \sin(\alpha )}</annotation></semantics></math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/95a2a215bb78a456fe5662229c73775521b95299" class="mwe-math-fallback-image-inline" aria-hidden="true" style="vertical-align: -0.838ex; width:6.153ex; height:2.843ex;" alt="{\displaystyle \sin(\alpha )}"></span> as well as <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \cos(\alpha )}"><semantics><mrow class="MJX-TeXAtom-ORD"><mstyle displaystyle="true" scriptlevel="0"><mi>cos</mi><mo>⁡<!-- ⁡ --></mo><mo stretchy="false">(</mo><mi>α<!-- α --></mi><mo stretchy="false">)</mo></mstyle></mrow><annotation encoding="application/x-tex">{\displaystyle \cos(\alpha )}</annotation></semantics></math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/8323c66f99d1f3b7e0858fb92b0644fb0b8fba8a" class="mwe-math-fallback-image-inline" aria-hidden="true" style="vertical-align: -0.838ex; width:6.408ex; height:2.843ex;" alt="{\displaystyle \cos(\alpha )}"></span>.
<a href="//commons.wikimedia.org/wiki/User:MartinThoma" title="User:MartinThoma">MartinThoma</a>
2015-11-05
<span class="int-own-work" lang="en">Own work</span>