A ={set of quadrilaterals}, B={square, rectangle, trapezium, rhombus}. State whether `A subset B or B subset A`. Justify your answer.

Is it right to say that sin (A+B) =sin A +sin B ? Justify your answer.

PQRS is a rectangle formed by joining the points P(-1, -1), Q(-1, 4), R(5,4) and S(5, -1) . A, B, C and D are the mid points of PQ, QR, RS and SR respectively. Is the quadrilateral ABCD a square, a rectangle or a rhombus? Justify your answer.

Is it true for any sets A and B, P(A) cup P(B)=P(A cup B)? Justify your answer.