Thursday

October 23, 2014

October 23, 2014

Posted by **victoria** on Monday, February 20, 2012 at 9:23am.

a)-9.004

b)-4.734

c)1.029

d)1.277

e)4.797

- calculus -
**Steve**, Monday, February 20, 2012 at 11:52amjust differentiate and solve. What's the trouble?

f = 3x^3*e^-x

f' = (9x^2 - 3x^3)e^-x

= 3x^2(3-x)e^-x

Now, x^2 >= 0 and e^-x >= 0

so the only way we can have f' < 0 is x>3

That means choice (e)

Check: 3*4.797^2*(3-4.797)e^-4.797 = -1.024

**Answer this Question**

**Related Questions**

Calculus - I have a two part question that pertains to a curve (r(x)) and its ...

Calculus - let f(x)=x*e^x For what value of x is the slope of the line tangent ...

Calculus: for mathmate - Find the slope of the tangent line to the graph of the ...

calculus totally confused - find a first degree polynomial function p(1) whose ...

Calculus - Find the slope m of the tangent line to the graph of the function at ...

Calculus - Find the slope m of the tangent line to the graph of the function at ...

Calculus PLEASE HELP - Find the slope m of the tangent line to the graph of the ...

Calculus - Find the slope m of the tangent line to the graph of the function at ...

calculus - find the point on the graph of the given function at which the slope ...

Applied Calculus...... - Find the slope m of the tangent line to the graph of ...