NIMCET 2012 — Mathematics PYQ
NIMCET | Mathematics | 2012If x=logabc, y=logbca and z=logcab, then 1+x1+1+y1+1+z1 is equal to:
Choose the correct answer:
- A.
abc
- B.
ab+bc+ca
1
Explanation
1. Simplify the denominator terms:
We know that 1=logaa.
1+x=logaa+logabc
Using the property logmn+logmp=logm(np):
1+x=loga(abc)
Similarly:
1+y=logbb+logbca=logb(abc)
1+z=logcc+logcab=logc(abc)
2. Simplify the reciprocals:
Using the base-change property logmn1=lognm:
1+x1=logaabc1=logabca
1+y1=logbabc1=logabcb
1+z1=logcabc1=logabcc
3. Sum the terms:
1+x1+1+y1+1+z1=logabca+logabcb+logabcc
Sum=logabc(a⋅b⋅c)
Sum=logabc(abc)
Sum=1
Conclusion:
The expression simplifies to 1.
Correct Option: (c)
Explanation
1. Simplify the denominator terms:
We know that 1=logaa.
1+x=logaa+logabc
Using the property logmn+logmp=logm(np):
1+x=loga(abc)
Similarly:
1+y=logbb+logbca=logb(abc)
1+z=logcc+logcab=logc(abc)
2. Simplify the reciprocals:
Using the base-change property logmn1=lognm:
1+x1=logaabc1=logabca
1+y1=logbabc1=logabcb
1+z1=logcabc1=logabcc
3. Sum the terms:
1+x1+1+y1+1+z1=logabca+logabcb+logabcc
Sum=logabc(a⋅b⋅c)
Sum=logabc(abc)
Sum=1
Conclusion:
The expression simplifies to 1.
Correct Option: (c)

