JEE Mains · Maths · STD 11 - Trigonometrical equations
If \(5, 5r, 5r^2\) are the lengths of the sides of a triangle, then \(r\) cannot be equal to
- A \(\frac{3}{4}\)
- B \(\frac{5}{4}\)
- C \(\frac{7}{4}\)
- D \(\frac{3}{2}\)
Answer & Solution
Correct Answer
(C) \(\frac{7}{4}\)
Step-by-step Solution
Detailed explanation
\(5,\,5r,\,5 r^{2}\) sides of triangle, \(5+5r > 5r^{2}\) ....... \((1)\) \(5+5r^{2} > 5r\) ....... \((2)\) \(5 r+5 r^{2} > 5\) ....... \((3)\) From \(r^{2}\,-\,r\,-\,1 < 0\) \(\left[r-\left(\frac{1-\sqrt{5}}{2}, \frac{1+\sqrt{5}}{2}\right)\right]\) ....... \((4)\) From \((2)\)…
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