Check whether the function f:R→R defined by f(x)=x^3+x, has any critical point/s or not ? If yes, then find the point/s

CBSE Class 12 Sample Paper for 2024 Boards
CBSE Class 12 Sample Paper for 2024 Boards
Last updated at Feb. 10, 2025 by Teachoo
Transcript
𝑓(𝑥)=𝑥3+𝑥 Finding 𝒇^′ (𝒙) 𝑓′(𝑥)= 3𝑥^2+1 Putting 𝒇′(𝒙)= 0 to find critical points 3𝑥^2+1 = 0 3𝑥^2=−1 𝒙^𝟐 = (−𝟏)/𝟑 x = ±√((−1)/3) x = ±√(𝟏/𝟑) 𝒊 So, x is an imaginary number But, given that x is a real number as 𝑓:ℝ→ℝ Therefore, there is no value of x ∈𝑅, when 𝒇′(𝒙)= 0 Thus, f(x) does not have any critical points