MathDB

11

Part of 2017 India PRMO

Problems(1)

2017 preRMO p11, f(x) = sin (x/3)+ cos (3x/10), f(n\pi +x)= f(x)

Source:

8/9/2019
Let f(x)=sin⁡x3+cos⁡3x10f(x) = \sin \frac{x}{3}+ \cos \frac{3x}{10} for all real xx. Find the least natural number nn such that f(nπ+x)=f(x)f(n\pi + x)= f(x) for all real xx.
trigonometryperiodic functionminimum