Fierfoxik,
<!DOCTYPE html>
<html>
<head>
<title>Untitled Page</title>
<style>
input[type='text']
{
width: 40px;
}
</style>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script>
<script>
$(function () {
$('.add_str').click(function () {
var mName = $('input[name = "mtrx_sel"]:checked').val()
var mId = '#matrix_' + mName;
$(mId + ' tr:first').clone().appendTo(mId);
$(mId + ' tr:last td input').each(function (indx, elem) {
$(elem).prop({ 'placeholder': mName + $(mId).get(0).rows.length + ',' + (indx + 1) });
});
});
$('.add_col').click(function () {
var mName = $('input[name = "mtrx_sel"]:checked').val()
var mId = '#matrix_' + mName;
$(mId + ' tr td:last').clone().appendTo(mId + ' tr');
$(mId + ' tr').each(function (indx, elem) {
var cells = $(elem).children();
$(elem.lastChild).children().prop({ 'placeholder': mName + (indx + 1) + ',' + cells.length });
});
});
})
</script>
</head>
<body>
<label>
<input checked="checked" name="mtrx_sel" type="radio" value="a" />Матрица А
</label>
<label>
<input name="mtrx_sel" type="radio" value="b" />Матрица Б
</label>
<br />
<button class="add_str btn-style" type="button">
<i class="fa fa-plus" aria-hidden="true"></i>Добавить строку</button>
<button class="add_col btn-style" type="button">
<i class="fa fa-plus" aria-hidden="true"></i>Добавить столбец</button>
<br />
Матрица А
<table id='matrix_a'>
<tr>
<td>
<input type='text' placeholder='a1,1' />
</td>
</tr>
<tr>
<td>
<input type='text' placeholder='a2,1' />
</td>
</tr>
</table>
Матрица Б
<table id='matrix_b'>
<tr>
<td>
<input type='text' placeholder='b1,1' />
</td>
</tr>
<tr>
<td>
<input type='text' placeholder='b2,1' />
</td>
</tr>
</table>
</body>
</html>