document.write( "Question 1204134: If y=x²+y²=2y, find dy/dx in terms of x and y. Prove that d²y/dx²=1/(1-y)³ \n" ); document.write( "
Algebra.Com's Answer #840199 by math_tutor2020(3817)\"\" \"About 
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\n" ); document.write( "Through a bit of trial-and-error, it appears the given equation should be \"x%5E2%2By%5E2+=+2y\".
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\n" ); document.write( "\n" ); document.write( "The 1st derivative would be: \"dy%2Fdx+=+x%2F%281-y%29\"
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2By%5E2+=+2y\"\r
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\n" ); document.write( "\n" ); document.write( "\"expr%28d%2F%28dx%29%29%28+x%5E2+%2B+y%5E2+%29+=+expr%28d%2F%28dx%29%29%282y%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"2x+%2B+2y%2Aexpr%28%28dy%29%2F%28dx%29%29+=+2%2Aexpr%28%28dy%29%2F%28dx%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"2x+=+2%2Aexpr%28%28dy%29%2F%28dx%29%29+-++2y%2Aexpr%28%28dy%29%2F%28dx%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"2x+=+%282+-++2y%29%2Aexpr%28%28dy%29%2F%28dx%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28dy%29%2F%28dx%29+=+%282x%29%2F%282-2y%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28dy%29%2F%28dx%29+=+%282x%29%2F%282%281-y%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28dy%29%2F%28dx%29+=+x%2F%281-y%29\"
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\n" ); document.write( "\n" ); document.write( "We then apply another round of implicit differentiation with respect to x.\r
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\n" ); document.write( "\n" ); document.write( "\"%28dy%29%2F%28dx%29+=+x%2F%281-y%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28d%5E2y%29%2F%28dx%5E2%29+=+expr%28d%2F%28dx%29%29%28x%2F%281-y%29%29\"\r
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\n" ); document.write( "\n" ); document.write( " Quotient Rule\r
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\n" ); document.write( "\n" ); document.write( "From here we plug in the first derivative\r
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\n" ); document.write( "\n" ); document.write( "\"%28d%5E2y%29%2F%28dx%5E2%29+=+%28%281-y%29%5E2%2Bx%5E2%29%2F%28+%281-y%29%5E3+%29\" \r
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\n" ); document.write( "\n" ); document.write( "\"%28d%5E2y%29%2F%28dx%5E2%29+=+%28%281-2y%2By%5E2%29%2Bx%5E2%29%2F%28+%281-y%29%5E3+%29\" \r
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\n" ); document.write( "\n" ); document.write( "\"%28d%5E2y%29%2F%28dx%5E2%29+=+%281-2y%2B%28x%5E2%2By%5E2%29%29%2F%28+%281-y%29%5E3+%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28d%5E2y%29%2F%28dx%5E2%29+=+%281-2y%2Bhighlight%282y%29%29%2F%28+%281-y%29%5E3+%29\" Use the equation x^2+y^2 = 2y\r
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\n" ); document.write( "\n" ); document.write( "\"%28d%5E2y%29%2F%28dx%5E2%29+=+1%2F%28+%281-y%29%5E3+%29\" \r
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\n" ); document.write( "\n" ); document.write( "Here's another way to do it \r
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\n" ); document.write( "\n" ); document.write( "\"%28dy%29%2F%28dx%29+=+x%2F%281-y%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"expr%28%28dy%29%2F%28dx%29%29%2A%281-y%29+=+x\"\r
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\n" ); document.write( "\n" ); document.write( " Product Rule\r
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\n" ); document.write( "\n" ); document.write( "\"expr%28%28d%5E2y%29%2F%28dx%5E2%29%29%2A%281-y%29+-+%28%28dy%29%2F%28dx%29%29%5E2+=+1\"\r
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\n" ); document.write( "\n" ); document.write( "\"expr%28%28d%5E2y%29%2F%28dx%5E2%29%29%2A%281-y%29+-+%28x%2F%281-y%29%29%5E2+=+1\" Plug in dy/dx = x/(1-y)\r
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\n" ); document.write( "\n" ); document.write( "\"expr%28%28d%5E2y%29%2F%28dx%5E2%29%29%2A%281-y%29+=+1+%2B+%28x%2F%281-y%29%29%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28d%5E2y%29%2F%28dx%5E2%29+=+%28%281-2y%2By%5E2%29%2Bx%5E2%29%2F%28%281-y%29%5E3%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28d%5E2y%29%2F%28dx%5E2%29+=+%281-2y%2B%28x%5E2%2By%5E2%29%29%2F%28%281-y%29%5E3%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28d%5E2y%29%2F%28dx%5E2%29+=+%281-2y%2B2y%29%2F%28%281-y%29%5E3%29%29\" Replace x^2+y^2 with 2y\r
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\n" ); document.write( "\n" ); document.write( "\"%28d%5E2y%29%2F%28dx%5E2%29+=+1%2F%28%281-y%29%5E3%29%29\"
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