Q.58 JAM 2024 MA Solution

I made little bit error in j substitution so you can interpret as tj-1 less than t less than tj
By j=1, t0 less than t less than t1
Similar j= 2
And then function f(t) = a0 + b0 t, a1+b1t,a2+b2t,a3+b3t for j = 1,2,3,4