\
d
)
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Apply half-angle formula:
.
\
(Substitute
)
\
\
\
\
The exact value of
.
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.![\"table](\"http://www.wiris.com/demo-aspx/pluginwiris3/fckeditor_wiris/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.aspx?formula=505b471043825c0391d7cf6667dff697.png\")
(Substitute ![\"italic](\"http://www.wiris.com/demo-aspx/pluginwiris3/fckeditor_wiris/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.aspx?formula=5239e1c52be823d31b3cf8592d6cf25f.png\")
)![\"table](\"http://www.wiris.com/demo-aspx/pluginwiris3/fckeditor_wiris/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.aspx?formula=407c936e72b8b4a6124c85710a14438f.png\")
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.