Originally Posted by

**lemontea** The demand function for a product is given by

*p*=*f*(*q*)=30 -Ö*q*

where *p* is the price per unit in dollars for *q* units. Use the linear approximation to approximate the the price when 224 units are demanded.

**Solution:** We want to approximate *f*(224). From

*f*(*q*) » *L*(*q*)=*f*(*a*)+*f*¢(*a*)(*q*-*a*)

and the fact that *f*¢(*a*)= a)-1/sqrt(a)

b) 1/(2sqrt(a))

c) - 1/(2sqrt(a))

d) 1/sqrt(a)

we choose *a*= ____________ .

From *f*(225)= ________ and *f*¢(225)= ________ we get *f*(224) » ______ .

Hence, the price per unit when 224 units are demanded is approximately $ _________ .