Finding Coefficient of x^25 in (2x - (3/x^2))^58

In summary, the coefficient of x^25 in (2x - (3/x^2))^58 is -5676647367067636376814212874240. This was calculated using the combination formula (58 choose k) multiplied by (2)^(58-k) * (-3)^k * (x)^(58-3k), where k is equal to 11. Despite the large number, this is the correct answer.
  • #1
Caldus
106
0
I get a number that is too big when I calculate the coefficient of x^25 in:

(2x - (3/x^2))^58

This is how I found the coefficient:

Code:
Note that (58) = A combination value...
           k

(58) * (2x)^(58-k) * (-3/x^2)^k
 k
(58) * (2)^(58 - k) * (x)^(58 - k) * (-3)^k * (1/x^2)^k
 k
(58) * (2)^(58 - k) * (-3)^k * (x)^(58 - k) * (x)^-2k
 k
(58) * (2)^(58 - k) * (-3)^k * (x)^(58 - 3k)
 k

58 - 3k = 25
-3k = -33
k = 11

So:

(58) * 2^47 * (-3)^11 * (x)^25
 11

This comes out to be a gigantic number. So I am unsure whether it is anywhere close to being correct despite that I thought that I followed the steps correctly. : \
 
Mathematics news on Phys.org
  • #2
Thats the right answer; -5676647367067636376814212874240
 
  • #3


Your calculations seem to be correct. The coefficient of x^25 in the given expression is indeed a very large number. However, it is important to note that this number is not the actual coefficient itself, but rather a numerical representation of it. In other words, the coefficient of x^25 is a combination of various terms and cannot be represented by a single number.

Also, it is important to consider the context in which this coefficient is being calculated. If this is for a mathematical problem or equation, the exact numerical value may not be as important as understanding the process and concept behind finding the coefficient. So while the number may seem too big, it is a valid result and can be used in further calculations or equations.

In summary, the coefficient of x^25 in (2x - (3/x^2))^58 is a large number, but it is a valid result obtained through the correct process. It may not be a single number, but rather a combination of terms. It is important to understand the concept and process behind finding coefficients rather than getting hung up on the numerical value.
 

1. How do I find the coefficient of x^25 in (2x - (3/x^2))^58?

The coefficient of x^25 in (2x - (3/x^2))^58 can be found by using the binomial theorem. The formula for finding the coefficient of a specific term in a binomial expansion is (n choose k) * a^(n-k) * b^k, where n is the power of the binomial, k is the term number starting from 0, a is the first term, and b is the second term. In this case, n = 58, k = 25, a = 2x, and b = -3/x^2. Plugging these values into the formula, we get (58 choose 25) * (2x)^(58-25) * (-3/x^2)^25 = 1.105 x 10^28.

2. Can I use a calculator to find the coefficient of x^25?

Yes, you can use a calculator to find the coefficient of x^25 in (2x - (3/x^2))^58. However, make sure that your calculator has a function for calculating combinations (n choose k) and can handle large numbers, as the result may be a very large number.

3. What if I want to find the coefficient of a different term?

The formula for finding the coefficient of a specific term in a binomial expansion is (n choose k) * a^(n-k) * b^k, where n is the power of the binomial, k is the term number starting from 0, a is the first term, and b is the second term. You can plug in different values for n, k, a, and b to find the coefficient of any desired term.

4. Can I find the coefficient of x^25 without using the binomial theorem?

Yes, you can find the coefficient of x^25 without using the binomial theorem by expanding the given expression using the binomial theorem and then identifying the term with x^25. However, this method may be more time-consuming and prone to errors compared to using the formula directly.

5. How does finding the coefficient of x^25 in (2x - (3/x^2))^58 relate to real-world applications?

Finding the coefficient of x^25 in (2x - (3/x^2))^58 is a common problem in mathematics and has applications in fields such as statistics, physics, and engineering. It can be used to calculate probabilities, determine coefficients in mathematical models, and solve various real-life problems involving binomial expansions.

Similar threads

Replies
17
Views
3K
Replies
3
Views
708
  • Linear and Abstract Algebra
Replies
2
Views
978
  • Calculus and Beyond Homework Help
Replies
3
Views
486
  • General Math
Replies
3
Views
1K
Replies
1
Views
1K
Replies
5
Views
2K
Replies
2
Views
1K
  • Calculus
Replies
3
Views
738
  • Precalculus Mathematics Homework Help
Replies
4
Views
785
Back
Top