Question

if tan A = root 2-1, then Sin A cos A= root 2/4

Answer 1

tan a=√2-1

tan square a =sec square a-1
sec square a=√2-1 +1
sec square a=√2
cos square a=1/√2

sin square a= 1- 1/√2

sin square a=√2-1/√2

sin a. cos a= √2/4