Given that f (x) = AX2 + BX is a even function defined on [a-1,2a], the key to find the value of a + B is why B is equal to 0 The key is why B equals 0!

Given that f (x) = AX2 + BX is a even function defined on [a-1,2a], the key to find the value of a + B is why B is equal to 0 The key is why B equals 0!


f(-x)=f(x)
So ax ^ 2-bx = ax ^ 2 + BX
2bx=0
So B = 0