document.write( "Question 1152038: what is the vertex, focus, and equation of directrix \r
\n" ); document.write( "\n" ); document.write( "(y+3)^2 = -4(x-2)
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Algebra.Com's Answer #773931 by MathLover1(20849)\"\" \"About 
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what is the vertex, focus, and equation of directrix\r
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\n" ); document.write( "\n" ); document.write( "The standard form is \"%28x+-+h%29%5E2+=+4p+%28y+-+k%29\", where the focus is (\"h\",\"+k+%2B+p\") and the directrix is \"y+=+k+-+p\". \r
\n" ); document.write( "\n" ); document.write( "If the parabola is rotated so that its vertex is (\"h\",\"k\") and its axis of symmetry is parallel to the \"x\"-axis, it has an equation of \"%28y+-+k%29%5E2+=+4p+%28x+-+h%29\", where the focus is (\"h+%2B+p\",\"+k\") and the directrix is\"+x+=+h+-+p\"\r
\n" ); document.write( "\n" ); document.write( "\"%28y%2B3%29%5E2+=+-4%28x-2%29\"......here you have an equation of rotated parabola in vertex form\r
\n" ); document.write( "\n" ); document.write( "so,
\n" ); document.write( "\"h=2\", \"k=-3\", \"4p=-4\"=>\"p=-1\" \r
\n" ); document.write( "\n" ); document.write( "= >vertex is at (\"2\",\"-3\")\r
\n" ); document.write( "\n" ); document.write( "=> focus is at (\"h+%2B+p\",\"+k\") =(\"2+-1\",\"+-3\") = (\"1\",\"-3\")\r
\n" ); document.write( "\n" ); document.write( "=> equation of directrix is \"+x+=+h+-+p\"=>\"+x+=+2+-+%28-1%29\"=>\"+x+=+2%2B1\"=>\"+x+=+3\"\r
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