Step-by-step explanation:
[tex]sin x \: cos x \: tanx = 1 - {cos}^{2} x \\ LHS \\= sin x \: cos x \: tanx \\ =sin x \: cos x \: \times \frac{sin x}{cos x} \\ = sin x \: \times \frac{sin x}{1} \\ ={sin}^{2} x \\ = 1 - {cos}^{2} x \\ = RHS \\ \therefore \: sin x \: cos x \: tanx = 1 - {cos}^{2} x \\ Hence \: Proved.[/tex]