Evaluate ∫_(t1)ᵗ2) x(τ) δ(τ - t0) dτ for:
a) x(τ) = cos(τ), t1=0, t2=2, t0=1
b) x(τ) = cos(2-τ), t1=0, t2=2, t0=3
c) x(τ) = τ²-1, t1=-2, t2=3, t0=0
d) x(τ) = sin(τ), t1=1, t2=3, t0=2