Attempt following question by selecting a choice to answer.
c
If cos
x = 0.25 then cos (
x2) =
B cA.
c0.652
B.
c0.791
C.
c0.725
D.
c0.57
c
B
Step 1: 2 cos2(x2) - 1 = cos x[Use double-angle formula.]
Step 2: 2 cos2(x2) = 1 + cos x[Simplify.]
Step 3: 2 cos2(x2) = 1 + 0.25 = 1.25[Substitute the value of cos x.]
Step 4: cos2(x2) = 0.625[Simplify.]
Step 5: cos (x2) = 0.625 = 0.790569 = 0.791[Find 0.625 and round it three decimal places.]
Step 6: Therefore, cos x2 = 0.791.