Q. If y(x)=(xxx),x>0 then dy2d2x+20 at x=1 is equal to:
Find First Derivative: First, we need to find the first derivative of y with respect to x. To do this, we will use the chain rule and the property that the derivative of xx is xx(1+ln(x)).Let's denote u=xx, so y=xu. Then we have:dxdy=dxd(xu)=u⋅xu−1+ln(x)⋅xu⋅dxduSince u=xx, we can also find dxdu using the same property:dxdu=xx(1+ln(x))Now we substitute dxdu back into the expression for x1.
Substitute dxdu: Substituting dxdu into the expression for dxdy, we get:dxdy=u⋅xu−1+ln(x)⋅xu⋅xx(1+ln(x))Simplifying, we have:dxdy=xx⋅xxx−1+ln(x)⋅xxx⋅xx(1+ln(x))
Find Second Derivative: Now we need to find the second derivative of y with respect to x, which is dx2d2y. This involves differentiating the expression for dxdy once more with respect to x. However, this is a very complex expression, and differentiating it directly is not straightforward. Instead, we will use the implicit differentiation technique by taking the natural logarithm of both sides of the original equation y=xxx and then differentiating.Let's take the natural logarithm of both sides:ln(y)=ln(xxx)Using the property of logarithms, we get:ln(y)=xx⋅ln(x)Now we differentiate both sides with respect to x.
Take Natural Logarithm: Differentiating both sides with respect to x, we get:dxd(ln(y))=dxd(xx⋅ln(x))Using the chain rule on the left side, we have:(y1)⋅dxdy=xx⋅ln(x)+xx⋅(1+ln(x))Now we need to isolate dxdy and then differentiate again to find dx2d2y.
Differentiate with Chain Rule: Multiplying both sides by y to isolate dxdy, we get: dxdy=y⋅(xx⋅ln(x)+xx⋅(1+ln(x))) Now we need to differentiate this expression with respect to x to find dx2d2y. However, this is where a mistake was made. The differentiation of the right side with respect to x is incorrect. The correct differentiation should take into account the product rule and the chain rule for the term xx⋅ln(x), which was not applied correctly.
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