My Math Forum Marginal cost with two variables, confused.

 Calculus Calculus Math Forum

 January 30th, 2014, 12:08 PM #1 Newbie   Joined: Jan 2014 Posts: 1 Thanks: 0 Marginal cost with two variables, confused. Your weekly cost to manufacture x bicycles and y tricycles is C(x,y)=20,000+60x+20y+50?(xy) a. What is marginal cost of manufacturing a bicycle. I derived x and got (25y^1/2)/x^(1/2) +60 but I dont know what to do next or if that is even right. b. What is the marginal cost of manufacturing a tricycle. I derived y and got (25x^1/2)/(y^1/2) +20 again I dont know what to do next c. What is the marginal cost of manufacturing a bicycle at a level of 10 bicycles and 10 tricycles? d. What is the marginal cost of manufacturing a tricycle at a level of 8 bicycles and 8 tricycles?
January 31st, 2014, 05:41 PM   #2
Math Team

Joined: Sep 2007

Posts: 2,409
Thanks: 6

Re: Marginal cost with two variables, confused.

I thought I had responded to this yesterday, but found it without a response this morning so repeated my response. Now I find no response again! Did I not post it right or did someone erase it or was this on three different boards?

Quote:
 Originally Posted by nakota2k Your weekly cost to manufacture x bicycles and y tricycles is C(x,y)=20,000+60x+20y+50?(xy) a. What is marginal cost of manufacturing a bicycle. I derived x and got (25y^1/2)/x^(1/2) +60 but I dont know what to do next or if that is even right.
Yes, that is the "partial derivative of C with respect to x". Strictly speaking the "marginal cost of manufacturing a bicycle" is the cost of manufacturing "one more bicycle", C(x+ 1, y)- C(x, y). For "large x", that can be approximated by $\partial C/\partial x$

Quote:
 b. What is the marginal cost of manufacturing a tricycle. I derived y and got (25x^1/2)/(y^1/2) +20 again I dont know what to do next c. What is the marginal cost of manufacturing a bicycle at a level of 10 bicycles and 10 tricycles?
Again, the exact value is C(11, 10)- C(10, 10) but that can be approximated by $\partial C/\partial x$ evaluated at x= 10, y= 10.

Quote:
 d. What is the marginal cost of manufacturing a tricycle at a level of 8 bicycles and 8 tricycles?

 January 31st, 2014, 06:31 PM #3 Global Moderator     Joined: Oct 2008 From: London, Ontario, Canada - The Forest City Posts: 7,968 Thanks: 1152 Math Focus: Elementary mathematics and beyond Re: Marginal cost with two variables, confused. @HallsofIvy: There's no record of such a deletion here (sitewide, from yesterday on).
 February 1st, 2014, 04:18 AM #4 Math Team   Joined: Sep 2007 Posts: 2,409 Thanks: 6 Re: Marginal cost with two variables, confused. So, my mind is going! Knew it would happen sooner or later.

 Tags confused, cost, marginal, variables

,

,

,

,

,

,

,

,

,

# the cost of 378 tricycles is rupees 4,71,366.what is the cost of one tricycles

Click on a term to search for related topics.
 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post mathkid Calculus 3 September 24th, 2012 08:20 PM mathkid Calculus 3 September 24th, 2012 08:17 PM kevpb Calculus 1 June 24th, 2012 09:40 PM Ian McPherson Calculus 0 November 23rd, 2011 08:40 AM esther_17 Calculus 2 October 25th, 2011 01:18 AM

 Contact - Home - Forums - Cryptocurrency Forum - Top