Real-valued solutions of exponential equation
CAT 2020 Slot 1 · Quantitative Ability · Hard · Inequalities
This is a hard Quantitative Ability question from the CAT 2020 Slot 1 paper. It tests Inequalities. The full answer key and a step-by-step explanation are below — try it yourself first, then reveal the solution.
The number of real-valued solutions of the equation is
- A.
infinite
- B.
0
- C.
1
- D.
2
B
Explanation
Let us analyze the Left Hand Side (LHS) and Right Hand Side (RHS):
-
LHS: . By AM-GM inequality, . Equality holds iff .
-
RHS: . Since , we have . Equality holds iff .
For LHS to equal RHS, both must equal 2 simultaneously. However, LHS at , while RHS at .
At : LHS , RHS . At : LHS , RHS .
Since there is no value of where LHS and RHS are equal, the number of real solutions is 0.
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