Typos and Errata
for
First Printing




p. 6, Computer Code 1.1 for Matlab: A ' is missing before the c--' in the 8th line. The line should read
plot(x,y3,'c--')

p. 13, Computer Code 1.2 for Matlab: The y in the 2nd line should be an x.

p. 16, Computer Code 1.3 for Matlab: (2 errors) There is no '.' needed before the ^ in the fourth line. The line should read int('exp(t^2)',t,2,3)
The line
syms t
also needs to be inserted between the 4th and 5th lines.

p. 26, problem #39: First x is missing power of 5; Equation should read
2x^5dy+(x^2y^4+1)ydx=0
p. 63, Computer Code 1.9 for Maple: The third line should not have "." before the "^". It should be
eq1:=(x^2+1)*diff....(the rest is fine)

p. 90, Computer Code 2.2 for Matlab: The correct final x-value in the first line should be 'xf=-1.2'

p. 101, problem #8: Change the IC in the last line to y(1)=0, to be consistent with stated problem.

p. 126, explicit solution on #8: The last term is negative:
y=(-1/2)(cos(x)+sin(x)-5exp(x))

p. 139, explicit solution on #8: The last term is negative:
y=(-1/2)(cos(x)+sin(x)-5exp(x))

p. 157, Problems 2, 3, 4: The middle term on the left side should have y', not y.

p. 204, Computer Code 4.1 for Maple: A ";" is missing at the end of the first line.

p. 211, 5th line: The general solution is from "Example 7 above"

p. 232, 3rd line (1st equation): The second term on the rhs is missing a "c2"

p. 250, 2nd eqn above (4.45): The 'D x sin x' should be 'E x sin x'

p. 321, Computer Code 5.3 for Mathematica: On the third line, MatrixForm is spelled incorrectly The line should be
MatrixForm[RowReduce[Transpose[A]]]

p. 336, 2nd line after equation (5.55): The second row is just the first row multiplied by i (not -i as stated).

p. 337, Problem 4c: The matrix should be -3, 6 in the first row and 2, 1 in the second row.

p. 340, last eqn in corollary 5.5.1: The factor on the right should be exp(at), i.e., the t should be in the exponent, not multiplied times the exp(a).

p. 418, Problem 3: The first part of the assumption should be ".95x.9 were initially susceptible".

p. 419, Problem 8c: The rhs of the s' equation of (6.59) should additionally have "+alpha*i*s" and the rhs of the i' equation of (6.59) should additionally have "+alpha*i^2"

p. 421, Problem 7b: The equations should be x' = x+3y, y' = -3x+y.

p. 466, Problem 14: The coefficient of dy/dx should be 7 (not 'y').

p. 478, Computer Code 7.4 for Maple: A ";" is missing at the end of the last three lines.

p. 483, Problem 39: The 't' on the right hand side of first equation should be in the exponent: '-e^(2t)'.

p. 483, Problem 40: The 't' on the right hand side of first equation should be in the exponent: '-5e^(3t)'.

p. 531, Computer Code 8.3 for Matlab (multiple errors): The 4th line should reference "eqODE" so that it is
eq1=collect(eqODE)
The lines that calculate the c-values should all reference eq4 (not eq3). Thus the two sets of lines should be
c1=subs(eq4.c1)
c2=subs(eq4.c2)
c3=subs(eq4.c3)

p. 532, Computer Code 8.3 for Maple: The 6th line should be commented out with a "#" for Maple; thus, # goes at the beginning of the line

p. 559, Problems 6: The 'p' should be a 'p^2' in the ODE.

p. 559, Problems 7 (2 typos): The 2nd power series to multiply by is e^{-x/(2t)}. The left hand side of the equation has base 'e' (the exponential).

p. 559, Problems 8: The coefficient of y in the ODE should be 'e^(-2t)'.

p. 577, Computer Code Example 4 for Maple: The 3rd line should be commented out with a "#" for Maple, instead of the "%" as written

p. 603, Computer Code C.1 for Maple: A ";" is missing at the end of the line that uses the linsolve command (9th command line from the bottom).

p. 610, equation (C.27): The "-2R_1" should be "-4R_1"

p. 610, Figure C.1: The second equation in EACH picture should be -x+y=2

p. 611, equation (C.30): The "R_2" should be "2R_2"

p. 617, equation (C.53): The "==" in the 2nd eqn should be "="

p. 631, answer to 1.2#27: The answer should be y=Cx^2-x

p. 631, answer to 1.2#29: The x should be in the numerator and the square root term in the denominator:
(+/- x)/sqrt(ln(x)+C)

p. 632, answer to 1.4#8: It IS exact, with answer (2cos x -1)y^2-2x = C

p. 632, answer to 1.4#16: The solution is for #15 (not #16 as given).

p. 632, answer to 1.5#48: Corrected answer is sqrt(y) = x^2 * ln|x| + C*x^2

p. 634, answer to 2.2#2a(ii):Corrected statement: "Solutions are unique everywhere except possibly y=-2."

p. 634, answer to 2.2#4: The "2"s should not be there. Correct answer is
y(x)=(x-1+sqrt(3))^2

p. 635, answer to 2.3#5: The "-2" is each of the pictures should be "-3" instead.

p. 643, answer to 4.5#5: The solution should be yp=Ax*e^(2x)sin(x)+Bx*e^(2x)cos(x)+Ce^(2x)sin(x)+Ee^(2x)cos(x)+F sin(x)+G cos(x).

p. 643, answer to 4.5#11: The solution should be A=11/17, B=-7/17.

p. 643, answer to 4.6#5: The solution should be yp=Ax*e^(2x)sin(x)+Bx*e^(2x)cos(x)+Ce^(2x)sin(x)+Ee^(2x)cos(x)+F sin(x)+G cos(x).

p. 643, answer to 4.6#11: The solution should be A=11/17, B=-7/17.

p. 653, answer to C.2#6b (multiple errors): The 3rd column should be "4", "0", "6". The determinant of the coefficient matrix is -14. The answers are x=-84/(-14)=6, y=-42/(-14)=3, z=14/(-14)=-1.



Thank you for reporting the above typos and errata. We appreciate your support!!



Send additional ones to:
Randall Swift (e-mail: rjswift "at" csupomona "dot" edu)
or
Stephen Wirkus (e-mail: swirkus "at" csupomona "dot" edu)