Trigonometry - Overview and Identities (15 of TBD) sin(2theta) and cos(2theta) Derived

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We will derive the identities sin[2(theta)]=2[sin(theta)cos(theta)] and cos[2(theta)]=1-2[sin(theta)]^2=2[cos(theta)]^2-1.

Title search on other platforms: Trigonometry - Overview and Identities (14 of TBD) [cos(A+B)][cos(A-B)] Derived

Title search on other platforms: Trigonometry - Overview and Identities (16 of TBD) sin(theta/2) Derived