Find angle .
The function is .
Substitute in above function.
At angle the beam of light enter the water if the beam travells at an angle of through the water.
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.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=6136c544cea56ae184ce80c46e0f76c5.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=cf294d24df17faacc335fc415f3ed948.png\")
in above function. ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=550ed9ac438f75576bdb73c0209281f8.png\")
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the beam of light enter the water if the beam travells at an angle of ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=5b6351952f96a3b078f173babcf65e4c.png\")
through the water.