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Please hint me

[SOLVED] please hint me

1. Homework Statement
28. What is the coefficient of [tex]x^{88}[/tex] from
[tex](x+1)(x+2)(x-3)(x+4)(x+5)(x-6)...(x+88)(x+89)(x-90)[/tex].

29. Find x from this equation [tex]\frac{108}{\sqrt{x^2-2916}}=\frac{378-x-\sqrt{x^2-2916}}{x+54}[/tex].


2. Homework Equations



3. The Attempt at a Solution
1. Homework Statement



2. Homework Equations



3. The Attempt at a Solution
 

Answers and Replies

tiny-tim
Science Advisor
Homework Helper
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28. What is the coefficient of [tex]x^{88}[/tex] from
[tex](x+1)(x+2)(x-3)(x+4)(x+5)(x-6)...(x+88)(x+89)(x-90)[/tex].
Hi mercedesbenz! :smile:

ok … a hint, as you asked for …

First, try answering: what are the coefficients of [tex]x^{90}[/tex] and of [tex]x^{89}[/tex] ? :smile:
29. Find x from this equation [tex]\frac{108}{\sqrt{x^2-2916}}=\frac{378-x-\sqrt{x^2-2916}}{x+54}[/tex].
You can simplify this slightly, before solving it:

Hint: what is √2916? What is 378/√2916? :smile:
 
Thank you so much I've already solved it.
 

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