Respuesta :

Answer:

see explanation

Step-by-step explanation:

Using the trigonometric identities

tan A = [tex]\frac{sinA}{cosA}[/tex] , cot A = [tex]\frac{cosA}{sinA}[/tex]

Consider the left side

(1 + cotA + tanA)(sinA - cosA)

each term in the second factor is multiplied by each term in the first factor.

1(sinA - cosA) + cotA(sinA - cosA) + tanA(sinA - cosA)

= sinA - cosA + cosA - [tex]\frac{cos^2A}{sinA}[/tex] + [tex]\frac{sin^2A}{cosA}[/tex] - sinA ( collect like terms )

= [tex]\frac{sin^2A}{cosA}[/tex] - [tex]\frac{cos^2A}{sinA}[/tex]

= ( sinA × [tex]\frac{sinA}{cosA}[/tex] ) - ([tex]\frac{cosA}{sinA}[/tex] × cosA )

= sinAtanA - cotAcosA

= right side ⇒ proven