Question

(sin77°÷cos13°)^2+(cos77°÷sin13°)^2-2cos^2 45°​

Answer 1

Step-by-step explanation:

(sin77°÷cos13°)^2+(cos77°÷sin13°)^2-2cos^2 45°

=(sin77°÷sin77°)^2+(cos77°÷cos77°)^2-2(1/√2)^2

=(1)^2+(1)^2-2(1/2)

=(1)+(1)-(2/2)

=1+1-1

=1