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How is cos (x) * cos (π / 6-x) = 1 / 2 * [cos (π / 6) + cos (2x - π / 6)] derived?
We use the integration and difference formula (COSA * CoSb = 1 / 2 [cos (a + b) + cos (a) (COS (a + b) + cos (a-b) as the integration and difference formula (COSA * CoSb = 1 / 2 [cos (a + B + cos (a + B) + cos (a-cos (a + b) + cos (a-b) (COS (a + b) + cos (a-b) (COS (a + b) + cos (a-cos (a + b) + cos (a-cos (a-cos (a-cos (a + b) + cos (COS (COS (a + b) + cos (COS (COS (COS (a + β) - cos (α + β) - cos (α + β) - cos (α - β (α - β) - cos (α - β) - cos (α - β) - cos (α - β) - cos (α - β) - cos (α - β) - cos (α - β) - cos (α - β) - cos (α - β) - cos (α - β) - cos (α[sin (α - β)] cos α sin β = 1 / 2 [sin (α + β) - sin (α - β)] Sum difference product formula: sin θ + sin φ = 2Sin (θ / 2 + θ / 2) cos (θ / 2 - φ / 2) sin θ - sin φ = 2cos (θ / 2 + φ / 2) sin (θ / 2 - φ / 2) cos θ + cos φ = 2cos (θ / 2 + φ / 2) cos (θ / 2 - φ / 2) cos θ - cos φ = - 2Sin (θ / 2 + φ / 2) sin (θ / 2 - φ / 2)
RELATED INFORMATIONS
- 1. 2 (- cos (π / 6) + isin (π / 6)) = 2 (COS (π - π / 6) + isin (π - π / 6)) why is π - π / 6? Who can tell me
- 2. It is proved that the nth power of (1 + cos θ + isin θ) = the nth power of 2 times the nth power of cos θ / 2 (COS n θ / 2 + isin n n θ / 2) Such as the title
- 3. The n-th root of non-zero complex R (COS θ + isin θ) is n complex numbers Is this something for Shanghai college entrance examination?
- 4. Verification: cos α + √ 3 · sin α = 2Sin (π / 6 + α). Need detailed process, thank you
- 5. Can (COS π / 4 + isin π / 4) ^ n be expressed as (Cosn π / 4 + Sinn π / 4)? Why? Here I ^ 2 = - 1
- 6. To prove sin1 / [Cosn ° * cos (n + 1) °] = Tan (n + 1) ° - Tan °
- 7. It is proved that XLN [(1 + x) / (1-x)] + cos x is greater than or equal to 1 + (x ^ 2) / 2 when (- 1 + x) / (1-x)]
- 8. Given the function f (x) = cos π X & nbsp; & nbsp; & nbsp; (x ≤ 0) f (x-1) + 1 & nbsp; & nbsp; (x > 0), then f (43) + F (- 43) =___ ．
- 9. On the derivation of half angle formula TaNx / 2 = under positive and negative root sign (1-cosx) / (1 + cosx) = (1-cosx) / SiNx Why is there no positive or negative in the last step
- 10. Please ask about proving Newton Leibniz formula Proof: let the upper limit be a variable, define a new function g [x], prove G '(x) = f (x), and then say g (x) C = f (x), but doesn't g (x) = f (x) C also hold?
- 11. The derivation of Maclaurin formula F (x) = ln (1 + x)
- 12. The McLaurin series of F (x) = x · cos (x ^ 2 / 2) is mainly used to find the n-th derivative of F (x)
- 13. McLaughlin formula of (e ^ x-1) / X expansion
- 14. Is there a similar formula for 1 / cos & # 178; X = sec & # 178; X?
- 15. The formula Sin & # 178; π / 2 = cos & # 178; π / 2=
- 16. What are the formulas of Sin & # 178; α = (1-cos (2 α)) / 2 and Sin & # 178; α = (1-sin (2 α)) / 2
- 17. Sin & # 178; X =? Cos & # 178; =? Theorem formula
- 18. If cos (x + π 4) = 45, X ∈ (− π 4, 0), then SiNx=______ ．
- 19. When x →∞, limx / SiNx = ∞
- 20. F '(SiNx) = cos ^ 2 (x), the calculation of F (x) needs detailed process, This is the exercise there