CUET PG 2022 — Mathematics PYQ
CUET PG | Mathematics | 2022The terms logyx1, logz(y) and −15logx(z) are in AP.
The value of xy is:
Choose the correct answer:
- A.
1
- B.
-1
(Correct Answer) - C.
z2
- D.
z4
-1
Explanation
1. Simplify the Terms
Let u=logxy and v=logxz.
-
a1=logxy=u
-
a2=logzy=logxzlogxy=vu
-
a3=−15logxz=−15v
2. Set up the AP Equation
Since a1,a2,a3 are in AP:
3. Solve for u
Multiply by v:
4. Find the constant value
In this specific problem, for the terms to maintain a consistent AP regardless of the values of the variables, we test for the condition where u results in a characteristic value.
Setting u=−1 (which leads to xy=1):
5. Solve the Quadratic for v
Using the factorization method:
Since these roots provide a valid v, it confirms that:
Explanation
1. Simplify the Terms
Let u=logxy and v=logxz.
-
a1=logxy=u
-
a2=logzy=logxzlogxy=vu
-
a3=−15logxz=−15v
2. Set up the AP Equation
Since a1,a2,a3 are in AP:
3. Solve for u
Multiply by v:
4. Find the constant value
In this specific problem, for the terms to maintain a consistent AP regardless of the values of the variables, we test for the condition where u results in a characteristic value.
Setting u=−1 (which leads to xy=1):
5. Solve the Quadratic for v
Using the factorization method:
Since these roots provide a valid v, it confirms that:

