Learn how to solve proving trigonometric identities problems step by step online. Prove the trigonometric identity tan(x)^21/(sec(x)^2)=1-cos(x)^2. Starting from the left-hand side (LHS) of the identity. Multiply the fraction by the term \tan\left(x\right)^2. Applying the secant identity: \displaystyle\sec\left(\theta\right)=\frac{1}{\cos\left(\theta\right)}. Divide fractions \frac{\tan\left(x\right)^2}{\frac{1}{\cos\left(x\right)^2}} with Keep, Change, Flip: a\div \frac{b}{c}=\frac{a}{1}\div\frac{b}{c}=\frac{a}{1}\times\frac{c}{b}=\frac{a\cdot c}{b}.

Prove the trigonometric identity tan(x)^21/(sec(x)^2)=1-cos(x)^2