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Example 15 - Chapter 3 Class 11 Trigonometric Functions
Last updated at April 16, 2024 by Teachoo
2x 3x formula - Finding value
Chapter 3 Class 11 Trigonometric Functions
Concept wise
- Radian measure - Conversion
- Arc length
- Finding Value of trignometric functions, given other functions
- Finding Value of trignometric functions, given angle
- (x + y) formula
- 2x 3x formula - Proving
-
2x 3x formula - Finding value
- cos x + cos y formula
- 2 sin x sin y formula
- Finding Principal solutions
- Finding General Solutions
- Sine and Cosine Formula
Transcript
Example 15 Prove that cos (π/4+𝑥) + cos (π/4−𝑥) = √2 cos 𝑥 Solving L.H.S. cos (π/4+𝑥) + cos(π/4−𝑥) = 2 cos ((π/4 " + " 𝑥 + π/4 " − " 𝑥 )/2) cos ((π/4 " + " 𝑥 − (π/4 " − " 𝑥) )/2) = 𝟐 𝒄𝒐𝒔𝛑/𝟒 𝒄𝒐𝒔𝒙 = 2 × 1/√2 cos𝑥 = √𝟐 𝒄𝒐𝒔𝒙 = R.H.S.
