3 Trigonometric Identities You Must Be Able To Derive From Scratch <br /> <br />Derive the trigonometric identities below from absolute scratch... <br /> <br />{cos(θ)}^2 + {sin(θ)}^2 = 1 <br /> <br />1 + {tan(θ)}^2 = {sec(θ)}^2 <br /> <br />{cot(θ)}^2 + 1 = {cosec(θ)}^2
