Section 5.5 { Double Angle Formulas

c Lynch 1 of 3 Section 5.5 { Double Angle Formulas Double Angle FormulasMEMORIZE! sin(2x) = 2sinxcosx cos(2x) = cos2 x sin2 x tan(2x) = sin(2x) cos(2x) Note. These formulas are derived from the sum formulas in 5.4 using 2x= x+x. The formula for cos2xcan also be written as cos(2x) = cos2 x sin2 x = 2cos2 x 1 = 1 2sin2 x The formula for tan(2x ... ................
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