For which values of r,`.^nC_r=^nP_r`?

For what value of r, ^8P_r is maximum?

Find the values of n and r if ""^nP_r=336,""^nC_r=56 .

Find the value of n if ^nP_5=42^nP_3,n>4

Find the value of n if ^nP_5:^nP_3=2:1 .

Find the value of n if ""^nC_14=""^nC_16 .

Find the value of n if ""^nP_3:""^nC_4=24:5

Write down the greatest value of ^20C_r and ^19C_r

Find the value of n if ""^54P_(r+3)=6840 xx ""^54P_(r+6)

Find the value of n if ""^nP_6=30 xx ""^nP_4 .

Explain the physical proces on the basis of which the r.m.s value of AC is defined? Derive the expression for r.m.s value of an alternating voltage. How does the value of Capacitative voltage. How does the value of Capacitative reactance of a capacitor change with the frequecny of the applied alternating e.m.f across it.