Problems chapter 1.7 fix.

[Danahi]

Problem 1.7.1 states "Build a 4×3 matrix with the numbers 1 through 4 in each row."

But it should be one of the following options:
"Build a 4×3 matrix with the numbers 1 through 4 in each column."
or
"Build a 3×4 matrix with the numbers 1 through 4 in each row."

[Danahi]

The same counts for question 3:
"Build a 4×3 matrix with the numbers 1 through 12 by row (meaning the first row will have the numbers 1 through 4 in it)."
should be:
"Build a 4×3 matrix with the numbers 1 through 12 by row (meaning the first row will have the numbers 1 through 3 in it)."
or
"Build a 3×4 matrix with the numbers 1 through 12 by row (meaning the first row will have the numbers 1 through 4 in it)."

[Danahi]

Question 16:
What should the other locations have for values? 0 or their original value?
It may be good to display the expected resulting matrix there.

[ericward-noaa]

@Danahi Thanks for catching these errors! I just updated the examples and incorporated your changes.

For 16, the B matrix should be a 3x3 matrix, with B[1,1], B[2,3] and B[3,2] = 1, with the rest of the elements = 0