Question

Let $f$ be a real-valued function satisfying $f(x+y)=f(x)+f(y)$ for all $x$, y. If $f(1)=\frac{1}{2}$, then the value of $f(16)$ is:

A. 16

B. 8

C. 4

D. 2

✨ Free AI Tools for You

Powered by Chatterbot AI

Answer

Given a real-valued function $f$ such that $f(x+y) = f(x) + f(y)$ for all real numbers $x$ and $y$, and given that $f(1) = \frac{1}{2}$, we are asked to find the value of $f(16)$.

Let's examine this step-by-step.

First, let's express $f(mx)$ where $m$ is an integer: $$ f(x + (m-1)x) = f(x) + f((m-1)x) $$ Using the given property repeatedly, $$ = f(x) + f(x + (m-2)x) = f(x) + f(x) + f((m-2)x) = \cdots = m f(x) + f(0) $$

Determining $f(0)$

Using the property $f(x+y) = f(x) + f(y)$: $$ \text{Putting } x = 0 \text{ and } y = 0, $$ $$ f(0+0) = f(0) + f(0) $$ $$ f(0) = 2f(0) \Rightarrow f(0) = 0 $$

Thus, the above expression simplifies to: $$ f(mx) = m f(x) \quad \text{where } m \text{ is an integer} $$

Finding $f(16)$

Given $f(1) = \frac{1}{2}$, $$ f(16 \times 1) = 16 f(1) $$ $$ f(16) = 16 \times \frac{1}{2} = 8 $$

Verification (Alternate )

Calculating successively: $$ f(2) = f(1) + f(1) = \frac{1}{2} + \frac{1}{2} = 1 $$ $$ f(4) = f(2) + f(2) = 1 + 1 = 2 $$ $$ f(8) = f(4) + f(4) = 2 + 2 = 4 $$ $$ f(16) = f(8) + f(8) = 4 + 4 = 8 $$

Therefore, the value of $f(16)$ is 8.


Was this helpful?

India's 1st AI Doubt Solver for CBSE, JEE, and NEET

Ask a Question for Free

and then it's just ₹212 a month

Learn how Chatterbot AI can help you succeed

Cover Image of the article Computer Science Class 11 CBSE - The Ultimate Guide with Notes, Solutions and AI

Computer Science Class 11 CBSE - The Ultimate Guide with Notes, Solutions and AI

This ultimate guide for CBSE Computer Science class 11 has detailed notes, NCERT solutions, cheat sheets, and our free AI-powered doubt-solving assistant, Chatterbot AI.

Cover Image of the article JEE Advanced 2024 Exam Date Announced: Complete Guide to Eligibility, Syllabus, and Preparation Tips

JEE Advanced 2024 Exam Date Announced: Complete Guide to Eligibility, Syllabus, and Preparation Tips

JEE Advanced 2024 on May 26! Get exam schedule, syllabus, prep tips & more in this guide. Ace India's top engineering test with topper strategies.

Cover Image of the article How to Crack NEET: The Ultimate Blueprint to Outsmart the Exam and Unlock Your Medical Dreams

How to Crack NEET: The Ultimate Blueprint to Outsmart the Exam and Unlock Your Medical Dreams

Ace NEET with expert strategies: Discover effective exam strategies, time management, core concepts mastery, problem-solving techniques, revision tips, and AI-assisted doubt clearing with Chatterbot AI.

Cover Image of the article How to Crack IIT: Smart Self-Study Strategies and AI Tools for Success

How to Crack IIT: Smart Self-Study Strategies and AI Tools for Success

Ace IIT JEE in 6 months without coaching. Discover expert self-study strategies for Physics, Chemistry, and Math. Master time management, mock tests, and leverage AI tools like Chatterbot AI for personalized doubt-solving.