A straight A student and maths medallist was reportedly "shattered" by yesterday's higher level paper, which prompted a deluge of complaints from teachers and students.
The student's mother said she found it "inexplicable" that the examiners would set a paper "so full of tricks and questions not covered on the syllabus".
"My daughter doesn't care if the exam is marked leniently because of this. The damage that's been done to her confidence today will affect her for the rest of the exams," she said.
One teacher described the paper as "a slap in the face" to students.
Yesterday's second higher level maths paper was described as "outrageous" by a subject expert from the Association of Secondary Teachers of Ireland (ASTI).
Many students were angry over a trigonometry question, which required a representation of the square root of three on a graph - an impossible task for students in an exam setting, according to one commentator.
"Students would only have been able to provide a sketch diagram in this instance," said Andrew Carolan of Ardee Community School.
"Trigonometry is very important for further development in maths," said Eileen Scanlon, ASTI subject convenor and a teacher at the Jesus and Mary Secondary School in Salthill.
"It's essential for anyone hoping to work in engineering or architecture. Students need to be assessed on basic trigonometry. This question was outrageously difficult. If we want students to be taught the basics of mathematics properly, we have to examine them properly. Today's paper was a slap in the face to students," she said.
Other commentators said the paper was more difficult than in previous years. Jim Healy of Terenure College said it was the hardest he had seen in four years and demanded independent thinking from students.
"This exam was a struggle for students who had learned off grind school notes or formula by heart and were depending on that to get them through," said Mr Healy. "There's a lesson in this for teachers. Kids must be able to think things through for themselves."
