ACT Math Practice Question #2126 (Hard) | Test Citadel
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ACT Math Difficulty: Hard

Digital ACT Math Practice Question #2126

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What is the maximum value of the function $f(x) = 4 - 7\cos(3x)$?
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Maximum occurs when subtracting a negative: $4 - 7(-1) = 11$.

Masterclass Solution & Distractor Trap Analysis

The cosine function oscillates between $-1$ and $+1$: $-1 \le \cos(3x) \le 1$. To maximize $4 - 7\cos(3x)$, we need $\cos(3x)$ to take its minimum value of $-1$: $f_{max} = 4 - 7(-1) = 4 + 7 = 11$....

Distractor Analysis: Trap choice eliminates careless test-takers who confuse roots with coordinates...

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