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Continuity & Differentiability · Question 89 of 125

What is f(-2) for this function?

Question 89

EasyOriginal question

Let f(x)=x∣x∣+∣x−1∣f(x) = x\lvert x \rvert + \lvert x - 1 \rvert.

What is f(−2)f(-2) for this function?

Options for question 89

Show the answer and explanation
CorrectNot quiteAnswer B

Correct answer: B

Explanation

  1. x∣x∣=(−2)(2)=−4x\lvert x \rvert = (-2)(2) = -4 and ∣−2−1∣=3\lvert -2 - 1 \rvert = 3.

  2. f(−2)=−4+3=−1f(-2) = -4 + 3 = -1.

Worth noting

7 takes x∣x∣x\lvert x \rvert as x2=4x^{2} = 4; for negative xx it is −x2-x^{2}.

Concept
Evaluating a modulus function
Typical time
90 s
Your time
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The rule this testsDifferentiability
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