ExamBro
ExamBro
TS EAMCET · Maths · Trigonometric Equations

If \(a, b\) are real numbers and \(\alpha\) is a real root of \(x^2+12+3 \sin (a+b x)+6 x=0\) then the value of \(\cos (a+b \alpha)\) for the least positive value of \(a+b \alpha\) is

  1. A -1
  2. B \(\frac{1}{\sqrt{2}}\)
  3. C \(\frac{1}{2}\)
  4. D 0
Verified Solution

Answer & Solution

Correct Answer

(D) 0

Step-by-step Solution

Detailed explanation

\((x+3)^2 + 3(1 + \sin (a+b x)) = 0\) Since \((x+3)^2 \ge 0\) and \(1+\sin (a+b x) \ge 0\), then \((x+3)^2 = 0\) and \(1+\sin (a+b x) = 0\). \(x = -3 \implies \alpha = -3\) \(\sin (a+b x) = -1\) \(\sin (a+b\alpha) = -1\) The least positive value for \(a+b\alpha\) is…