Question:

The period of function f(x) = \(e^{log(sinx)}+(tanx)^3 - cosec(3x - 5)\)is

Updated On: May 4, 2025
  • π

  • π/2

  • 2π/3

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The Correct Option is C

Solution and Explanation

To solve the problem, we need to find the period of the function $f(x) = e^{\log(\sin x)} + (\tan x)^3 - \csc(3x-5)$ by analyzing each term separately.

1. Analyzing the First Term:
The first term is $e^{\log(\sin x)} = \sin x$.
The period of $\sin x$ is $2\pi$.

2. Analyzing the Second Term:
The second term is $(\tan x)^3$.
The period of $\tan x$ is $\pi$, so the period of $(\tan x)^3$ is also $\pi$.

3. Analyzing the Third Term:
The third term is $\csc(3x-5)$.
The period of $\csc x$ is $2\pi$, so the period of $\csc(3x-5)$ is $\frac{2\pi}{3}$.

4. Determining the Overall Period:
The period of $f(x)$ is the least common multiple of the periods of the individual terms ($2\pi$, $\pi$, and $\frac{2\pi}{3}$), which is $2\pi$.

5. Considering the Domain:
The function $f(x)$ is only defined where $\sin x > 0$, which occurs in intervals $(2n\pi, (2n+1)\pi)$ for integer $n$.
Additionally, $\tan x$ must be defined, so $x \neq (2n+1)\frac{\pi}{2}$.
Thus, the domain is $x \in (2n\pi, (2n+1)\pi) \setminus \{(2n+1)\frac{\pi}{2}\}$.

6. Final Period Determination:
Despite the restricted domain, the pattern repeats every $2\pi$ units.
The least common multiple of all periods is $2\pi$, which matches the periodicity of the defining condition ($\sin x > 0$).

Final Answer:
The period of $f(x)$ is ${2\pi}$.

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Concepts Used:

Trigonometric Equations

Trigonometric equation is an equation involving one or more trigonometric ratios of unknown angles. It is expressed as ratios of sine(sin), cosine(cos), tangent(tan), cotangent(cot), secant(sec), cosecant(cosec) angles. For example, cos2 x + 5 sin x = 0 is a trigonometric equation. All possible values which satisfy the given trigonometric equation are called solutions of the given trigonometric equation.

A list of trigonometric equations and their solutions are given below: 

Trigonometrical equationsGeneral Solutions
sin θ = 0θ = nπ
cos θ = 0θ = (nπ + π/2)
cos θ = 0θ = nπ
sin θ = 1θ = (2nπ + π/2) = (4n+1) π/2
cos θ = 1θ = 2nπ
sin θ = sin αθ = nπ + (-1)n α, where α ∈ [-π/2, π/2]
cos θ = cos αθ = 2nπ ± α, where α ∈ (0, π]
tan θ = tan αθ = nπ + α, where α ∈ (-π/2, π/2]
sin 2θ = sin 2αθ = nπ ± α
cos 2θ = cos 2αθ = nπ ± α
tan 2θ = tan 2αθ = nπ ± α