Let be the sum of all coefficients in the expansion of . If the equations and have a common root, then equals:
- A
- B
- C
- D
Let be the sum of all coefficients in the expansion of . If the equations and have a common root, then equals:
Correct answer:D
Standard Method
Given: is the sum of all coefficients of . The equations and have a common root.
Find: The ratio .
From the solution, the sum of coefficients is obtained by substituting :
Hence, .
The solution then concludes that the correct option is D and states the required ratio as .
There is inconsistency in the extracted working for and in the intermediate justification, but the solution explicitly identifies D as the correct option.
Therefore, the correct option is D, so .
Using the sum of coefficients incorrectly. For a polynomial, the sum of coefficients is found by substituting , not by adding visible terms manually. Evaluate the entire expression at first.
Assuming every line of the extracted solution is internally consistent. Here the intermediate working for is contradictory, so the final marked option on the solution must be treated.
Mixing up the ratio order. The question asks for , so even if intermediate symbols are discussed in a different order, the final comparison must be made in the exact order requested.
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