Trig Fns - Identities

Evaluate trig expressions using angle sum and difference identities

Expand expressions using angle sum and difference identities

Applications of angle sum and difference identities

Evaluate trig expressions using double and half angle identities

Expand expressions using double and half angle identities

Apply double and half angle identities

Sums and differences as products (deg)

Sums and differences as products (rad)

Apply sum and difference and double angle identities

Solve equations using trigonometric identities

Prove and apply other trigonometric identities

Class XI

Expand expressions using double and half angle identities

Interactive practice questions

Using the double angle identity for the cosine ratio, simplify the expression $\cos^2\left(4x\right)-\sin^2\left(4x\right)$cos2(4x)−sin2(4x).

Express your answer as a single trigonometric function.

Easy

1min

Outcomes

11.SF.TF.1

Positive and negative angles. Measuring angles in radians and in degrees and conversion from one measure to another. Definition of trigonometric functions with the help of unit circle. Truth of the identity sin^2 x + cos^2 x = 1, for all x. Signs of trigonometric functions and sketch of their graphs. Expressing sin (x + y) and cos (x + y) in terms of sin x, sin y, cos x and cos y. Deducing the identities like following: cot(x + or - y), sin x + sin y, cos x + cos y, sin x - sin y, cos x - cos y (see syllabus document)

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