Given: g(x) is an even function, then
f(x)=∫0xg(t)dt will be an odd function,
⇒f(−x)=−f(x)
Let I=∫0xf(t)dt put t=z+5
⇒I=∫−5x−5f(z+5)dz
⇒I=∫−5x−5g(z)dz (∵f(x+5)=g(x))
⇒I=∫−5x−5f′(z)dz(∵f′(x)=g(x))
⇒I=f(z)∣−5x−5=f(x−5)−f(−5)
⇒I=f(5)−f(5+x) ( f is an odd function and g is given as an even function)
⇒I=∫5+x5f′(t)dt=∫5+x5g(t)dt