Solve Indicial Equations with Step-by-Step Homework Help

  • Thread starter Thread starter juliany
  • Start date Start date
AI Thread Summary
The discussion focuses on solving two indicial equations: 3^(2x) - 36*3^x = -243 and 5(x+2)^2 = 80. For the first equation, the user attempts to rewrite it as 3^(2x) * 3^x = -207 and suggests substituting y = 3^x. In the second equation, the user expands it to 5x^2 + 20x + 20 = 80 and simplifies to 5x^2 + 20x = 60, indicating a need for further steps. The advice includes factoring and recognizing common factors to simplify the equations. Overall, the discussion emphasizes the importance of substitution and simplification in solving indicial equations.
juliany
Messages
11
Reaction score
0

Homework Statement


I'm just confused about a few little indicial equations.

1. 3^2x-36X3^x=-243
2.5(x+2)^2=80


The Attempt at a Solution


1.3^2x X 3^x=-207


2.5(x^2+4x+4)=80
5x^2+20x+20=80
5x^2+20x=60

Unsure what to do after both of them.
 
Physics news on Phys.org
For the first one...realize that 32x=(3x)2 and then put y=3x

For the second one, even though you didn't really need to square out and expand, just factorize it. But since 5 is a common factor, divide by 5 first.
 
I picked up this problem from the Schaum's series book titled "College Mathematics" by Ayres/Schmidt. It is a solved problem in the book. But what surprised me was that the solution to this problem was given in one line without any explanation. I could, therefore, not understand how the given one-line solution was reached. The one-line solution in the book says: The equation is ##x \cos{\omega} +y \sin{\omega} - 5 = 0##, ##\omega## being the parameter. From my side, the only thing I could...
Back
Top