save_figs = F

# Question 22:
#
A = matrix( c( 1, 1, -2, 1 ), nrow=2, ncol=2, byrow=T )
b = c( 1, 0 )
x = solve( A, b )
print(x)

b = c( 0, 1 )
x = solve( A, b )
print(x)


# Question 23:
#
A = matrix( c( exp(-3), exp(-1), -3*exp(-3), -exp(-1) ), nrow=2, ncol=2, byrow=T )
b = c( 1, 0 )
x = solve( A, b )
print(x)

b = c( 0, 1 )
x = solve( A, b )
print(x)

print( c( -0.5*exp(3), 1.5*exp(1) ) ) # check with the numbers in the back of the book