find the interval in which the function f(x)= cos3x, 0<= x<= pie/2 is increasing or decreasing Share with your friends Share 0 Rahul Raj answered this dear student f(x)=cos3xf'(x)=-3sin3xf'(x)=0sin3x=03x=nπx=nπ/3for x∈0,π/2n can only take value n=1x=π/3for x∈0,π/3, f'(x)=-3sin3x ≤0and x∈π/3,π/2, f'(x)=-3sin3x ≥0so f(x) is decreasing in for x∈0,π/3and increasing for x∈π/3,π/2 regards 0 View Full Answer
