Definite IntegrationeasyFree

∫ [arg|z|] dx from 0 to 100 with z ≠ 0 | JEE

JEE Maths question with a full step-by-step solution.

Question
If z0z\ne 0, then x=0100[argz]dx\displaystyle\int_{x=0}^{100}\big[\arg|z|\big]\,dx, where [][\,\cdot\,] denotes the greatest integer function, is
A00correct
B1010
C100100
Dnot defined
Solution
Step 1: Examine z|z|. For any non-zero complex number zz, the modulus z|z| is a positive real number, lying on the positive real axis of the complex plane. Step 2: A positive real number has argument 00, so
argz=0.\arg|z|=0.
Step 3: Apply the greatest integer function: [argz]=[0]=0\big[\arg|z|\big]=[0]=0. This is a constant, independent of the integration variable xx. Step 4: Integrate the constant zero:
01000dx=0.\int_{0}^{100}0\,dx=0.
Correct answer: (1)
Still stuck on this question?Ask your doubt on WhatsApp
Similar questions

Solve more, learn faster

Sign up free to solve more JEE Maths questions and explore doMath — timed drills, mastery sprints, bookmarks, and chapter-wise progress tracking.