JEE Main2018MathematicsContinuity and DifferentiabilityActual
Let S = λ , μ ∈ R × R : f t = λ e t - μ sin ⁡ 2 t , t ∈ R is a differential function . Then, S is a subset of :
Options
- A- ∞ ,  0 × R
- BR × 0 ,  ∞ )
- C0 , ∞ ) × R
- DR × - ∞ , 0
Correct answer
B. R × 0 ,  ∞ )
Step-by-step solution
Let S = λ ,   μ ∈ R × R and f t = λ e t - μ .   sin ⁡ 2 t R H D = lim h → 0 ⁡ f 0 + h - 0 h = lim h → 0 ⁡ λ e h - μ sin 2 ⁡ h h = 2 ( λ - μ ) L H D = lim h → 0 ⁡ f 0 - h - 0 - h = lim h → 0 ⁡ λ e h - μ sin 2 ⁡ h - h = - 2 ( λ - μ ) Now, L H D = R H D if λ = μ ⇒ μ ≥ 0 and λ ∈ R