Hi , i will like to know how did the graph in a translates into b? by differentiation?

(a) Q Q = 100/0.5 (K = 100) S P M R Q =7010.5 (K = 49) N Short-run production functions for K = 100 and K = 49 (b) MPL, APL APL = 70L-0.5 MPL and APL for short-run production function Q =7010.5 MPL = 35L-0.5 0 Because the slope of tangent NM in (a) remains positive however large L becomes, the MPL curve in (b) never cuts the L-axis. As MPL is always less than APL, this means that APL curve also never cuts the L-axis. 4.19 Short-run production functions, MPL and APL, for production function Q = 1010.510.5