If find the value of .

26

In a right triangle ABC, right angled at B, if tan A = 1, then verify that 2 sin A cos A = 1.

27

If 4sin² θ =3 and 0^o < θ <90^o, find the value of 1 + cos θ.

29

If 13 cos θ = 5, .

30

If , show that =3.