Solution :
Draw a right angled triangle ABC right angled at B.
Let ∠ A = θ, then ∠ C = 90 – θ
sin A = sinθ = BCAC ……..(1)
cos C = cos(90–θ) = BCAC ……..(2)
From (1) and (2), we have
cos(90–θ) = sinθ
Draw a right angled triangle ABC right angled at B.
Let ∠ A = θ, then ∠ C = 90 – θ
sin A = sinθ = BCAC ……..(1)
cos C = cos(90–θ) = BCAC ……..(2)
From (1) and (2), we have
cos(90–θ) = sinθ