Question #81d94

1 Answer
Aug 27, 2016

y^'=x^(x^2+1)(2ln(x)+1)

Explanation:

First, use the rule that (a^b)^c=a^((bc) so y=x^((x*x))=x^(x^2). We have:

y=x^(x^2)

Take the natural logarithm of both sides:

ln(y)=ln(x^(x^2))

Simplifying this using log(a^b)=blog(a):

ln(y)=x^2ln(x)

Differentiate both sides. On the left side, the chain rule will kick into effect, since this is a function of y and not x. On the right hand side, we will use the product rule (if y=fg, then y^'=f^'g+fg^').

We get:

1/y*y^'=(x^2)^'ln(x)+x^2(ln(x))^'

The derivative of x^2 is 2x and of ln(x) is 1/x:

1/y*y^'=2xln(x)+x^2(1/x)

1/y*y^'=x(2ln(x)+1)

Now, solve for y^' by multiplying both sides of the equation by y.

y^'=yx(2ln(x)+1)

Since y=x^(x^2):

y^'=x^(x^2)x(2ln(x)+1)

Simplify x^(x^2)x using the rule a^ba^c=a^(b+c):

y^'=x^(x^2+1)(2ln(x)+1)