Use T4(x), at an appropriate x-value, rounded to five decimal places to estimate cos(34°).

Question

Let f(x) = cos(x). Then  T₄(x) centered at a = π/6 is

(sqrt(3)/2) - (1/2)(x-(π/6)) - (sqrt(3)/4)(x-(π/6))^2 + (1/12)(x-(π/6))^3 + (sqrt(3)/48)(x-(π/6))^4

Use T₄(x), at an appropriate x-value, rounded to five decimal places to estimate cos(34°).

Answer 1

34° = 34(π/180) = 17π/90 is the x-value to use to get the estimate.