Find the slope of the demand curve D(p) = 20 / sqrt (p-1), p>1, at point (5,10)

The demand slope is given by D(p) = 20 / sqrt (p -
1)

The slope of the curve is the value of the first
derivative at the required point.

D(p) = 20 / sqrt (p -
1)

=> 20* ( p -
1)^(-1/2)

D'(p) = 20*(-1/2)*(p
-1)^(-3/2)

At the point (5, 10), the slope
is

D'(5) = -20*(1/2)*(5
-1)^(-3/2)

=>
-20*(1/2)*(4)^(-3/2)

=>
-20*(1/2)/8

=>
-20/16

=>
-1.25

The slope of the demand graph at (5,
10) is -1.25.