Explanation:
The given equation is:
logab × logbc = 0
Rule of logarithms:
If logab = x, then ax = b
Using the above rule of logarithms:
logab × logbc = 0
If logab = x, then ax = b
If logbc = y, then by = c
Therefore, we can rewrite the given equation as:
ax × by = 1
Since ax and by are both positive, their product can only be equal to 1 if both ax and by are equal to 1.
Using the above conclusion:
Therefore, we have:
ax = 1 and by = 1
If ax = 1, then x = 0 (since a0 = 1 for any positive value of a)
If by = 1, then y = 0 (since b0 = 1 for any positive value of b)
Therefore, we have:
logab = 0 and logbc = 0
If logab = 0, then b = a0 = 1
If logbc = 0, then c = b0 = 1
Therefore, we have:
b = 1 and c = 1
Substituting these values in the original equation, we get:
loga1 × log11 = 0
Since loga1 = 0 (for any positive value of a) and log11 = 0, we have:
0 × 0 = 0
Conclusion:
Therefore, the given equation logab × logbc = 0 is true if and only if b = 1 and c = 1.