Question

cos45º.cos60° - sin45°. sin60° =
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Answer 1

Answer:

cos(105º) = { 1 - [3^(1/2)] } / { [2^(1/2)].2 }

Step-by-step explanation:

cos45º.cos60° - sin45°. sin60º = { [1 / 2^(1/2)] . (1/2) } - { [1 / 2^(1/2)] . [3^(1/2)] / 2]

cos(45º+60º)                              = { 1 / [2^(1/2)].2 } - { [3^(1/2)] / 2.(2^(1/2)] }

cos(105º)                                     = { 1 - [3^(1/2)] } / { [2^(1/2)].2 }