Loading [MathJax]/jax/output/SVG/jax.js
 
+0  
 
0
1194
4
avatar+1904 

Use logarithmic differentation to find the derivative of the function.

 

y=xex2(x2+1)10

 

Anyone who knows how to solve for the answer and can write down the steps, I would really appreciate it.  Thanks.

 May 22, 2018
 #1
avatar
0

It uses implicit differentiation:

d/dx(y) = d/dx({e^(x^2) sqrt(x) (1 + x^2)^10})

 

The derivative of y is y'(x):

y'(x) = d/dx({e^(x^2) sqrt(x) (1 + x^2)^10})

 

Using the chain rule, d/dx({e^(x^2) sqrt(x) (x^2 + 1)^10}) = ( du)/( du) ( du)/( dx), where u = e^(x^2) sqrt(x) (x^2 + 1)^10 and d/( du)({u}) = {1}:

y'(x) = {d/dx(e^(x^2) sqrt(x) (1 + x^2)^10)}

 

Use the product rule, d/dx(u v) = v ( du)/( dx) + u ( dv)/( dx), where u = e^(x^2) and v = sqrt(x) (x^2 + 1)^10:

y'(x) = {sqrt(x) (x^2 + 1)^10 d/dx(e^(x^2)) + e^(x^2) d/dx(sqrt(x) (1 + x^2)^10)}

 

Using the chain rule, d/dx(e^(x^2)) = ( d e^u)/( du) ( du)/( dx), where u = x^2 and d/( du)(e^u) = e^u:

y'(x) = {e^(x^2) (d/dx(sqrt(x) (1 + x^2)^10)) + e^(x^2) d/dx(x^2) sqrt(x) (1 + x^2)^10}

Use the power rule, d/dx(x^n) = n x^(n - 1), where n = 2.

d/dx(x^2) = 2 x:

y'(x) = {e^(x^2) (d/dx(sqrt(x) (1 + x^2)^10)) + 2 x e^(x^2) sqrt(x) (1 + x^2)^10}

 

Simplify the expression:

y'(x) = {2 e^(x^2) x^(3/2) (1 + x^2)^10 + e^(x^2) (d/dx(sqrt(x) (1 + x^2)^10))}

 

Use the product rule, d/dx(u v) = v ( du)/( dx) + u ( dv)/( dx), where u = sqrt(x) and v = (x^2 + 1)^10:

y'(x) = {2 e^(x^2) x^(3/2) (1 + x^2)^10 + (x^2 + 1)^10 d/dx(sqrt(x)) + sqrt(x) d/dx((1 + x^2)^10) e^(x^2)}

 

Use the power rule, d/dx(x^n) = n x^(n - 1), where n = 1/2.

d/dx(sqrt(x)) = d/dx(x^(1/2)) = x^(-1/2)/2:

y'(x) = {2 e^(x^2) x^(3/2) (1 + x^2)^10 + e^(x^2) (sqrt(x) (d/dx((1 + x^2)^10)) + 1/(2 sqrt(x)) (1 + x^2)^10)}

 

Using the chain rule, d/dx((x^2 + 1)^10) = ( du^10)/( du) ( du)/( dx), where u = x^2 + 1 and d/( du)(u^10) = 10 u^9:

y'(x) = {2 e^(x^2) x^(3/2) (1 + x^2)^10 + e^(x^2) ((1 + x^2)^10/(2 sqrt(x)) + 10 (x^2 + 1)^9 d/dx(1 + x^2) sqrt(x))}

Differentiate the sum term by term:

y'(x) = {2 e^(x^2) x^(3/2) (1 + x^2)^10 + e^(x^2) ((1 + x^2)^10/(2 sqrt(x)) + d/dx(1) + d/dx(x^2) 10 sqrt(x) (1 + x^2)^9)}

 

The derivative of 1 is zero:

y'(x) = {2 e^(x^2) x^(3/2) (1 + x^2)^10 + e^(x^2) ((1 + x^2)^10/(2 sqrt(x)) + 10 sqrt(x) (1 + x^2)^9 (d/dx(x^2) + 0))}

 

Simplify the expression:

y'(x) = {2 e^(x^2) x^(3/2) (1 + x^2)^10 + e^(x^2) ((1 + x^2)^10/(2 sqrt(x)) + 10 sqrt(x) (1 + x^2)^9 (d/dx(x^2)))}

 

Use the power rule, d/dx(x^n) = n x^(n - 1), where n = 2.

d/dx(x^2) = 2 x:

y'(x) = {2 e^(x^2) x^(3/2) (1 + x^2)^10 + e^(x^2) ((1 + x^2)^10/(2 sqrt(x)) + 2 x 10 sqrt(x) (1 + x^2)^9)}

 

Simplify the expression:

 

| y'(x) = {2e^(x^2) x^(3/2) (1 + x^2)^10 + e^(x^2) (20 x^(3/2) (1 + x^2)^9 + (1 + x^2)^10/(2 sqrt(x)))}  [Courtesy of Mathematica 11 Home Edition]

 May 22, 2018
 #2
avatar+1904 
0

This may be the right answer; however, the instructions say to use logarithmic differentation.  If anyone knows how to solve for the answer usin logarithmic differentation, I would really appreciate it.  Thanks.

gibsonj338  May 22, 2018
 #3
avatar
0

It gives this answer using "Logarithmic Differentiation", but does not give step by step answer. Sorry about that:

 

Log(y'(x) = 2e^(x^2) x^(3/2) (x^2 + 1)^10 + (e^(x^2) (x^2 + 1)^10)/(2 sqrt(x)) + 20 e^(x^2) x^(3/2) (x^2 + 1)^9). Note: it uses natural logs.

 May 22, 2018
 #4
avatar+26396 
+1

Use logarithmic differentation to find the derivative of the function.

y=xe(x2)(x2+1)10

y=\sqrt{x}{e}^{(x^2)}(x^2+1)^{10}

Anyone who knows how to solve for the answer and can write down the steps?

 

Formula

( lnf(x) )=f(x)f(x)

 

1. logarithm of both sides

y=xe(x2)(x2+1)10|ln() both sidesln(y)=ln(x)+ln(e(x2))+ln((x2+1)10)ln(y)=ln(x12)+ln(e(x2))+ln((x2+1)10)|Formula: ln(ab)=bln(a)ln(y)=12ln(x)+x2ln(e)+10ln(x2+1)|Formula: ln(e)=1ln(y)=12ln(x)+x2+10ln(x2+1)

 

2. derivation of both sides

ln(y)=12ln(x)+x2+10ln(x2+1)|derivate both sides(ln(y))=(12ln(x))+(x2)+(10ln(x2+1))yy=121x+2x+102xx2+1yy=12x+2x+20xx2+1|yy=y(12x+2x+20xx2+1)|y=xe(x2)(x2+1)10y=xe(x2)(x2+1)10(12x+2x+20xx2+1)y=x12e(x2)(x2+1)10(12x+2x+20xx2+1)y=x12e(x2)(x2+1)102x+x12e(x2)(x2+1)102x+x12e(x2)(x2+1)1020xx2+1y=e(x2)(x2+1)102x112+2e(x2)x12+1(x2+1)10+20e(x2)x12+1(x2+1)101(x2+1)1y=e(x2)(x2+1)102x12+2e(x2)x32(x2+1)10+20e(x2)x32(x2+1)101y=e(x2)(x2+1)102x+2e(x2)x32(x2+1)10+20e(x2)x32(x2+1)9

 

y=e(x2)(x2+1)102x+2e(x2)x32(x2+1)10+20e(x2)x32(x2+1)9

 

laugh

 May 23, 2018

0 Online Users