<p>Please help.</p>
<p>What is d^2y/dx^2 (second derivitive when differentiated implicitly) of :</p>
<p>x^2 + 4y^2 = 7 + 3xy</p>
<p>(the first derivitive is: dy/dx=(3y-2x)/(8y-3x))</p>
<p>Thanks</p>
<p>y'=(3y-2x)/(8y-3x)
y''=[(8y-3x)(3y'-2)-(3y-2x)(8y'-3)]/(8y-3x)^2</p>
<p>i got (-7(x+y))/(8y-3x) ssquared</p>
<p>i agree with devious_...., thats what i got too. lol what'd u do z2thay? i just learned this stuff recently..tryin to see if i missed somethin in simplifyin it. sry if i sound ignorant to u guys...new to this..lol</p>
<p>Well, I got what devious got, but a lot of my signs are flipped around. Naturally distraught, I reworked it another way to get what devious got, but then I realized that the signs make little difference. In the original equation, the x and y values are squared on the left, so the sign obviously does not matter there. On the second side, since the x and y are multiplied together, if x is either positive or negative, then y will be either negative or positive, the opposite. So as long as y is negative throughout the solution and x is positive, it is mathematically the same as what devious got. Correct? If not, please make fun of me, but I am pretty sure I am right.</p>