Respuesta :

Space

Answer:

cos(2π/35)

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

  1. Brackets
  2. Parenthesis
  3. Exponents
  4. Multiplication
  5. Division
  6. Addition
  7. Subtraction
  • Left to Right

Pre-Calculus

  • Sum/Difference Formula [cosine]: [tex]\displaystyle cos(x \pm y) = cos(x)cos(y) \mp sin(x)sin(y)[/tex]

Step-by-step explanation:

Step 1: Define

Identify

cos(π/5)cos(π/7) + sin(π/5)sin(π/7)

Step 2: Simplify

  1. Sum/Difference Formula [cosine]:                                                                   cos(π/5)cos(π/7) + sin(π/5)sin(π/7) = cos(π/5 - π/7)
  2. Subtract:                                                                                                            cos(π/5 - π/7) = cos(2π/35)