Math Problem Statement

lim (π‘₯,𝑦)β†’(0,0) 𝑦5 π‘₯4 +𝑦2

Solution

The given expression is:

lim⁑(x,y)β†’(0,0)y5x4+y2\lim_{(x, y) \to (0, 0)} \frac{y^5}{x^4 + y^2}

To determine whether this limit exists, we need to check if the limit value depends on the path taken towards the origin (0,0)(0, 0).

Approach 1: Along the xx-axis (y=0y = 0)

Substitute y=0y = 0 into the expression:

05x4+02=0x4=0\frac{0^5}{x^4 + 0^2} = \frac{0}{x^4} = 0

So, along the xx-axis, the limit is 0.

Approach 2: Along the yy-axis (x=0x = 0)

Substitute x=0x = 0 into the expression:

y504+y2=y5y2=y3\frac{y^5}{0^4 + y^2} = \frac{y^5}{y^2} = y^3

As (x,y)β†’(0,0)(x, y) \to (0, 0), y3β†’0y^3 \to 0. So, along the yy-axis, the limit is also 0.

Approach 3: Along the line y=mxy = mx (for some constant mm)

Substitute y=mxy = mx into the expression:

(mx)5x4+(mx)2=m5x5x4+m2x2=m5x5x2(x2+m2)\frac{(mx)^5}{x^4 + (mx)^2} = \frac{m^5 x^5}{x^4 + m^2 x^2} = \frac{m^5 x^5}{x^2(x^2 + m^2)}

Factor out x2x^2:

=m5x3x2+m2= \frac{m^5 x^3}{x^2 + m^2}

As x→0x \to 0, the numerator approaches 00, and the denominator approaches m2m^2, so the limit is:

lim⁑xβ†’0m5x3x2+m2=0\lim_{x \to 0} \frac{m^5 x^3}{x^2 + m^2} = 0

Conclusion:

Based on these paths (the xx-axis, the yy-axis, and the line y=mxy = mx), the limit appears to be 00 along each approach. Hence, we conclude:

lim⁑(x,y)β†’(0,0)y5x4+y2=0\lim_{(x, y) \to (0, 0)} \frac{y^5}{x^4 + y^2} = 0

If you'd like more details or another approach to this problem, feel free to ask!


Related Questions:

  1. How do you check the limit of a multivariable function using polar coordinates?
  2. What happens if the numerator or denominator has a higher degree than the other in such limits?
  3. What does it mean if the limit depends on the path taken?
  4. How can you apply the epsilon-delta definition of limits in multivariable functions?
  5. How does the squeeze theorem apply to limits involving two variables?

Tip:

When checking multivariable limits, testing along various paths is a good initial approach. If the limit value changes based on the path, the limit does not exist.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Multivariable Calculus
Limits
Path-Dependent Limits

Formulas

lim_{(x, y) β†’ (0, 0)} f(x, y)

Theorems

Limit of multivariable functions along various paths

Suitable Grade Level

Grades 11-12