Let L1, L2 are regular and L3, L4 are context free grammar. Whether the following is true or false. For each, prove your answer. (You can use counter example if
necessary)
a) L1 ∪ L2 is regular.
b) L1 ∩ L2 is regular.
c) L3 ∪ L4 is context free.
d) L3 ∩ L4 is context free

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

What are the two (02) benefits, which may result from a successful implementation of preventive maintenance (pm) program in an organization? (clo3)a)- lean manufacturing b)-overlapping responsibilities c)-the planner is not qualified d)-accurate contractor information e)-reduction in equipment redundancies f)-accurate stores information

Aturning operation is performed with following conditions: rake angle of 12°, a feed of 0.35 mm/rev, and a depth of cut of 1.1 mm. the work piece is aluminum alloy 6061 with t6 heat treatment (a16061-t6). the resultant chip thickness was measured to be 1.0 mm. estimate the cutting force, fc. use shear stress of 207 mpa and coefficient of friction on the tool face of 0.6.