Question 85 of 1,000
Machine Learning and Deep LearningmediumMultiple ChoiceObjective-mapped

Activation Functions: ReLU vs Tanh for Vanishing Gradients

This AI0-001 practice question tests your understanding of machine learning and deep learning. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

A deep learning model for sentiment analysis uses a softmax output layer. The hidden layers currently use tanh activation. Which activation function should replace tanh to mitigate vanishing gradients in deeper networks?

Quick Answer

The answer is ReLU. Unlike tanh, which saturates at extreme values and produces near-zero gradients that stall learning in deeper layers, ReLU’s output is unbounded for positive inputs, allowing gradients to flow freely and directly addressing the vanishing gradient problem. This concept is central to the CompTIA AI+ AI0-001 exam, where you must recognize that activation functions to mitigate vanishing gradients must avoid saturation; a common trap is assuming tanh’s zero-centered output is always superior, but in deep networks its saturating tails still cause gradient decay. A reliable memory tip is “ReLU lets the gradient through—tanh slams the door.”

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

ReLU

ReLU (Rectified Linear Unit) is correct because it outputs zero for negative inputs and a positive linear slope for positive inputs, which avoids the saturation problem of tanh. In deeper networks, tanh gradients can vanish as activations approach ±1, slowing or halting learning. ReLU's non-saturating nature keeps gradients flowing for positive inputs, mitigating the vanishing gradient problem.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Sigmoid

    Why it's wrong here

    Sigmoid also saturates and causes vanishing gradients.

  • Softmax

    Why it's wrong here

    Softmax is used only in output layers for multi-class probabilities.

  • ReLU

    Why this is correct

    ReLU is non-saturating and helps mitigate vanishing gradients.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Linear

    Why it's wrong here

    Linear activation reduces network to a linear model, losing expressiveness.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Candidates often mistakenly believe that any non-linear activation works equally well in deep networks, but the trap is that they may choose sigmoid because it is non-linear, ignoring its saturation-induced vanishing gradient problem in deeper architectures.

Trap categories for this question

  • Command / output trap

    Softmax is used only in output layers for multi-class probabilities.

Detailed technical explanation

How to think about this question

ReLU introduces sparsity by zeroing out negative inputs, which can lead to 'dead neurons' if a large gradient forces weights into a region where the neuron never activates. In practice, variants like Leaky ReLU or Parametric ReLU are used to address this. For sentiment analysis, ReLU's computational efficiency and gradient preservation make it a standard choice for hidden layers in deep architectures like CNNs or RNNs.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A practitioner preparing for the AI0-001 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.

Quick reference

OSI Model Reference

LayerNamePDUKey Protocols / Devices
7ApplicationDataHTTP, HTTPS, DNS, SMTP, FTP, SSH
6PresentationDataTLS / SSL, JPEG, ASCII encoding
5SessionDataNetBIOS, RPC, SIP
4TransportSegment / DatagramTCP, UDP
3NetworkPacketIP, ICMP, OSPF — Routers
2Data LinkFrameEthernet, Wi-Fi, PPP — Switches, Bridges
1PhysicalBitsCables, NICs, Hubs, Repeaters

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FAQ

Questions learners often ask

What does this AI0-001 question test?

Machine Learning and Deep Learning — This question tests Machine Learning and Deep Learning — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: ReLU — ReLU (Rectified Linear Unit) is correct because it outputs zero for negative inputs and a positive linear slope for positive inputs, which avoids the saturation problem of tanh. In deeper networks, tanh gradients can vanish as activations approach ±1, slowing or halting learning. ReLU's non-saturating nature keeps gradients flowing for positive inputs, mitigating the vanishing gradient problem.

What should I do if I get this AI0-001 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jul 4, 2026

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This AI0-001 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AI0-001 exam.