Log In Start studying!

Select your language

Suggested languages for you:
Answers without the blur. Sign up and see all textbooks for free! Illustration

Q4.3-4E

Expert-verified
Fundamentals Of Differential Equations And Boundary Value Problems
Found in: Page 172
Fundamentals Of Differential Equations And Boundary Value Problems

Fundamentals Of Differential Equations And Boundary Value Problems

Book edition 9th
Author(s) R. Kent Nagle, Edward B. Saff, Arthur David Snider
Pages 616 pages
ISBN 9780321977069

Answers without the blur.

Just sign up for free and you're in.

Illustration

Short Answer

The auxiliary equation for the given differential equation has complex roots. Find a general solution. y''-10y'+26y=0

The auxiliary equation for the given differential equation y''-10y'+26y=0 has complex roots and its general solution is y(t)=e5t(c1cos(t)+c2sin(t)).

See the step by step solution

Step by Step Solution

Step 1: Complex conjugate roots.

If the auxiliary equation has complex conjugate roots α±, then the general solution is given as:

y(t)=c1eαtcosβt+c2eαtsinβt

Step 2: The auxiliary equation.

Assume that y=ert is a solution to the given equation.

Since the given equation is of order two, differentiate role="math" localid="1654061985491" y with respect to role="math" localid="1654061981089" x twice:

y'(t)=rerty"(t)=r2ert

Substitute y",y' and y in the given equation to obtain: ert(r2-10r+26)=0.

Then the auxiliary equation is r2-10r+26=0.

Step 3: Finding the roots.

Solve for the roots of the auxiliary equation

r1/2=10±102-4×1×262×1 =10±100-104 =10±2i =5±i

Step 4: Final answer.

Since it has a complex conjugate of the form r=α± for α=5 and β=1

Thus, the general solution is y(t)=e5t(c1cos(t)+c2sin(t)).

Recommended explanations on Math Textbooks

94% of StudySmarter users get better grades.

Sign up for free
94% of StudySmarter users get better grades.