Question:
If x = sin14 x + cos20 x, then write the smallest interval in which the value of x lie.
Solution:
If $x=0^{\circ}, 90^{\circ}, 180^{\circ}, 270^{\circ}, 360^{\circ}$, then $\sin ^{14} x+\cos ^{20} x$ will always be $1 .$
The smallest interval in which the value of $x$ lie is $(0,1]$.