Question

giúp vs

Answer 1

a: TXĐ: D=R\{0}

Khi \(x\in D\) thì \(-x\in D\)

\(f\left(-x\right)=\dfrac{sin\left(-3x\right)}{-x}=\dfrac{-sin3x}{-x}=\dfrac{sin3x}{x}=f\left(x\right)\)

=>f(x) chẵn

b: ĐKXĐ: x<>kpi và sin x<>0

=>x<>kpi

=>D=R\{kpi}

\(x\in D\Leftrightarrow-x\in D\)

\(f\left(-x\right)=cot\left(-x\right)-\dfrac{2}{sin\left(-x\right)}\)

\(=-cotx+\dfrac{2}{sinx}=-f\left(x\right)\)

=>f(x) lẻ