(A)C1≡(1,3),r1=√1+9−9=1
and C2≡(−3,1),r2=√9+1−1=3
Now, |C1C2|=√16+4=√20=2√5>r1+r2
Hence, circles neither cuts nor touch each other.
∴ Point of intersection=0
⇒λ=0
and μ=4 (i.e., 2 direct common tangents and 2 transverse common tangents)
∴λ+μ=4
μ−λ=4
λμ+μλ=1
Options (3,4) are correct
(B)C1≡(3,0),r1=3
and C2≡(−1,0).r2=1
Now, C1C2=4=r1+r2
Hence, circles touch each other externally.
∴ Point of intersection is one
∴λ=1 and μ=3
∴λ+μ=4
μ−λ=2
and λμ+μλ=13+31=4
(C)C1≡(1,2),r1=√1+4−1=2
and C2≡(2,1),r2=√4+1−1=2
∴|C1C2|=√2
∵|r1−r2|<|c1c2|<r1+r2
Hence, circles cuts at two points.
∴ Point of intersection is two
∴λ=2,μ=2;
λ+μ=4
μ−λ=0
λμ+μλ=22+22=8