Сompute Irrational roots of the equation y 3 − 3 y = y + 2

Question

Сompute Irrational roots of the equation       y    3    −  3  y  =      y    +    2

zlepljalz2 · Accepted Answer

After your substitution we obtain  cos  ⁡  3  θ  =      |    cos    ⁡          θ      2        |  1.   cos  ⁡  3  θ  =  cos  ⁡      θ    2   gives  3  θ  =  ±      θ    2    +      360          ∘        k  ,where   k  ∈      Z  , which gives   x  =      144          ∘        k or   x  =            720              ∘              7    k  ..Now, since   cos  ⁡  3  θ  ≥  0, we obtain here:  x  =  2  cos  ⁡      144          ∘      or  x  =  2  cos  ⁡            720              ∘              7    .The case   cos  ⁡  3  θ  =  −  cos  ⁡      θ    2   for you.

Сompute Irrational roots of the equation

Answered question

Answer & Explanation

New Questions in Algebra I