ICSE BoardEnglish MediumSTD 9MATHEMATICSIrrational Numbers3 Marks
Question
Write a pair of irrational numbers whose product is irrational.
✓
Answer
Consider two irrational numbers $(5+\sqrt{2})$ and $(\sqrt{5}-2)$.
Thus, we have
$(5+\sqrt{2})(\sqrt{5}-2) $
$=5(\sqrt{5}-2)+\sqrt{2}(\sqrt{5}-2)$
$=5 \sqrt{5}-10+\sqrt{10}-2 \sqrt{2}$ , which is irrational.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.