Question

Please tell me the answer how to do this ​

Answer 1

→The Sarrus diagram , or the rule of Sarrus is used to easily find the terms in a determinant . Let us denote a determinant by its diagonal elements . So determinant. So , the rule of Sarrus helps in finding the positive and negative terms of the determinant

→In linear algebra, Cramer's rule is an explicit formula for the solution of a system of linear equations with as many equations as unknowns, valid whenever the system has a unique solution. Cramer's rule implemented in a naïve way is computationally inefficient for systems of more than two or three equations.

Answer 2

Answer:

Hope my answer helps you mate

Step-by-step explanation:

See the diagram enclosed .. of Cos x from 0 to 2π.

We need the area under the curve (enclosed between X-axis and the curve).

Bounded area = 

So Answer = 4 

  Bounded Area = Area A1 + Area A2 + Area A3 + Area A4.

  From symmetry of the curve we know that all the above four areas are equal.

We can also prove that by taking integrals for each of these parts.