JEE Mains · Maths · STD 11 - Trigonometrical equations
If an angle \(A\) of a \(\Delta ABC\) satisfies \(5\,cos\,A+3 = 0,\) then the roots of the quadratic equation, \(9x^2 + 27x+ 20 = 0\) are
- A \(sin\,A,\,\,sec\,A\)
- B \(sec\,A,\,\,tan\,A\)
- C \(tan\,A,\,\,cos\,A\)
- D \(sec\,A,\,\,cot\,A\)
Answer & Solution
Correct Answer
(B) \(sec\,A,\,\,tan\,A\)
Step-by-step Solution
Detailed explanation
\(\text { Here, } 9 x^{2}+27 x+20=0\) \(\therefore x=\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\) \(\Rightarrow x=\frac{-27 \pm \sqrt{27^{2}-4 \times 9 \times 20}}{2 \times 9}\) \(\Rightarrow x=-\frac{4}{3},-\frac{5}{3}\) \(\text { Given, } \cos A=-\frac{3}{5}\)…
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