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Mathematics - Trigonometric Equation Question with Solution | TestHub

MathematicsTrigonometric EquationTrigonometric EquationMedium2 minPYQ_2016

MathematicsMediumsingle choice

If $0 \leq x < 2 π,$ then the number of real values of $x,$ which satisfy the equation $\cos x + \cos 2 x + \cos 3 x + \cos 4 x = 0,$ is

Options:

Answer:

Solution:

$2 \cos 2 x \cos x + 2 \cos 3 x \cos x = 0$

$\Rightarrow$ $2 \cos x (\cos 2 x + \cos 3 x) = 0$

$2 \cos x 2 \cos \frac{5 x}{2} \cos \frac{x}{2} = 0$

$x = \frac{π}{2}, \frac{3 π}{2}, π, \frac{π}{5}, \frac{3 π}{5}, \frac{7 π}{5}, \frac{9 π}{5}$

$7$ Solutions.

Stream:JEESubject:MathematicsTopic:Trigonometric EquationSubtopic:Trigonometric Equation

⏱ 2mℹ️ Source: PYQ_2016

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