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Is-dy-dx-if-y-3-x-3-2x-1-




Question Number 98895 by bramlex last updated on 17/Jun/20
Is (dy/dx) if y^3 +x^3 −2x=1 ?
$${Is}\:\frac{{dy}}{{dx}}\:{if}\:{y}^{\mathrm{3}} +{x}^{\mathrm{3}} −\mathrm{2}{x}=\mathrm{1}\:?\: \\ $$
Answered by bramlex last updated on 17/Jun/20
Answered by mathmax by abdo last updated on 17/Jun/20
y^3  +x^3 −2x =1 ⇒y^3  =−x^3  +2x+1 ⇒y =(−x^3  +2x+1)^(1/3)  ⇒  (dy/dx) =(1/3)(−3x^2  +2)^(−(2/3))  =(1/(3(^3 (√((−3x^2 +2)^2 )))))
$$\mathrm{y}^{\mathrm{3}} \:+\mathrm{x}^{\mathrm{3}} −\mathrm{2x}\:=\mathrm{1}\:\Rightarrow\mathrm{y}^{\mathrm{3}} \:=−\mathrm{x}^{\mathrm{3}} \:+\mathrm{2x}+\mathrm{1}\:\Rightarrow\mathrm{y}\:=\left(−\mathrm{x}^{\mathrm{3}} \:+\mathrm{2x}+\mathrm{1}\right)^{\frac{\mathrm{1}}{\mathrm{3}}} \:\Rightarrow \\ $$$$\frac{\mathrm{dy}}{\mathrm{dx}}\:=\frac{\mathrm{1}}{\mathrm{3}}\left(−\mathrm{3x}^{\mathrm{2}} \:+\mathrm{2}\right)^{−\frac{\mathrm{2}}{\mathrm{3}}} \:=\frac{\mathrm{1}}{\mathrm{3}\left(^{\mathrm{3}} \sqrt{\left(−\mathrm{3x}^{\mathrm{2}} +\mathrm{2}\right)^{\mathrm{2}} }\right)} \\ $$

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