1974 AHSME Problems/Problem 3
Problem
The coefficient of in the polynomial expansion of
is
Solution
Let's write out the multiplication, so that it becomes easier to see.
We can now see that the only way to get an is by taking three and one . There are ways to pick which term the comes from, and the coefficient of each one is . Therefore, the coefficient of is .
See Also
1974 AHSME (Problems • Answer Key • Resources) | ||
Preceded by Problem 2 |
Followed by Problem 4 | |
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