1.
Let Z1=(8+i)sin⁡θ+(7+4i)cos⁡θZ_1 = (8 + i)\sin\theta + (7 + 4i)\cos\theta and Z2=(1+8i)sin⁡θ+(4+7i)cos⁡θZ_2 = (1 + 8i)\sin\theta + (4 + 7i)\cos\theta be two complex numbers. If Z1⋅Z2=a+ibZ_1 \cdot Z_2 = a + ib where a,b∈Ra, b \in \mathbb{R}, then the largest value of (a+b)(a + b) for ∀θ∈R\forall \theta \in \mathbb{R} is