Question

I=\int _0^1\int _0^1\frac{1}{1-x^2y^2}

Answer 1

$\huge{\underline{\mathtt{\red{A}\pink{N}\green{S}\blue{W}\purple{E}\orange{R}}}}$

History is the scientific study of the past. Events occurring before the invention of writing systems are considered prehistory. "History" is an umbrella term that relates to past events as well as the memory, discovery, collection, organization, presentation, and interpretation of information about these events.