Question

[PRECALC] Verify the following trigonometric identity using sin2x + cos2x = 1

Answer 1

See below ~

Explanation:

Identities :

1. cot x = cos x / sin x
2. sin²x + cos²x = 1

Changing the Left Hand Side (LHS) :

• 1/cot x + cotx
• 1/(cos x / sin x) + cos x / sin x
• sin x / cos x + cos x / sin x
• Take (sin x)(cos x) as the LCM (Least Common Multiple)
• sin x (sin x) + cos x (cos x) / (sin x) (cos x)
• sin²x + cos²x / cos x sin x
• 1/cos x sin x
• Equal to the RHS