Q. 22

# Prove the following with the help of identities:sin8θ – cos8θ = (sin2θ – cos2θ) (1– 2sin2θ cos2θ)

Taking L.H.S we get,

Sin8 θ– cos8 θ

Using the formula: a2 – b2 = (a – b)(a + b)

(sin4 θ – cos4 θ)(sin4 θ + cos4 θ)

(sin2 θ – cos2 θ)(sin2 θ + cos2 θ)((sin2 θ + cos2 θ)2 – 2.sin2 θ.cos2 θ)

(sin2 θ – cos2 θ)(1)((1)2 – 2.sin2 θ.cos2 θ) (Using: sin2 θ + cos2 θ = 1.)

(sin2 θ – cos2 θ)(1 – 2.sin2 θ.cos2 θ)

= R.H.S

Hence, proved

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Trigonometric Identities33 mins
Basic Concepts of Trigonometry45 mins
Champ Quiz | Trigonometric Identities33 mins
Smart Revision | Trigonometric Identities40 mins
Applying the Trigonometric Identities52 mins
NCERT | Trigonometric Identities52 mins
Trigonometric Identities44 mins
Solving NCERT Questions on Trigonometric Identities56 mins
Algebraic Identities48 mins
Quiz | Practice Important Questions on Trigonometrical Identities46 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses