Idk but I think my homies know this
Step-by-step explanation:











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The correct answer is C, 6/7
$4.47 is the required cost.
Answer:
cos x ≠ 0 ⇔ x ≠
; k ∈ N

<=> cos²x + sin²x = 1
⇔ 1 = 1
=> x = { R \ (pi/2 + k.pi); k ∈ N}
Step-by-step explanation: