How do you express cos( (4 pi)/3 ) * cos (( pi) /4 ) cos(4π3)⋅cos(π4) without using products of trigonometric functions?
1 Answer
I suggest , use "Sum of Trigonometric Functions"
Explanation:
Use Double-Angle Formulas
Add the left side terms equals the sum of the right terms:
it follows
Use the given: Let
it follows
Finally, after simplification
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