Let f be a non-negative function defined on the interval [0,1]. If integral0xsqrt(1−(f′(t))2) dt = integral0xf(t) dt,0≤x≤1, and f(0)=0, then (1)f(21)<21 and f(31)>31(2)f(21)>21 and f(31)>31(3)f(21)<21 and f(31)<31(4)f(21)>21 and f(31)<31
∫0x1−(f′(t))2dt=∫0xf(t)dt,0≤x≤1f≥0 on [0,1],f(0)=0Which of (1)-(4) is TRUE?1.differentiate both sides (FTC)2.solve for f3.compare f(1/2),f(1/3) with 1/2,1/3dxd:1−(f′(x))2=f(x)1−(f′)2=f2⇒f2+(f′)2=1,f(0)=0,f≥0⇒f(t)=sintf(21)=sin21<21,f(31)=sin31<31(sinx<x)⇒option (3)