Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
707 views
in Derivatives by (49.4k points)
closed by

f(x) = (sin x - cos x) is decreasing in

A. (0, 3π/4)

B. (3π/4, 7π/4)

C. (7π/4, 2π)

D. none of these

1 Answer

+1 vote
by (50.9k points)
selected by
 
Best answer

Answer is : B. (3π/4, 7π/4)

Given:

f(x) = sin x – cos x

f’(x) = cos x + sin x

Multiply and divide by √2.

For f(x) to be decreasing .f’(x)<0

∴ f(x) decreases in the interval.

⇒ (3π/4, 7π/4)

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...