Question:medium

The equation of the tangent to the curve x5/2 + y5/2 = 33 at the point(1, 4) is:

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When differentiating implicitly, always remember to apply the chain rule when dealing with terms involving \( y \), as \( y \) is treated as a function of \( x \). This means that when differentiating \( y^2 \), you must also include \( \frac{dy}{dx} \). Once you have derived \( \frac{dy}{dx} \), you can use it to find the slope at a specific point, and from there, you can write the equation of the tangent line using the point-slope form of the line equation.

Updated On: Mar 27, 2026
  • x + 8y − 33 = 0
  • 12x + y − 8 = 0
  • x + 8y − 12 = 0
  • x + 12y − 8 = 0
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The Correct Option is A

Solution and Explanation

The equation of the tangent to the curve \(x^{5/2}+y^{5/2}=33\) at point (1, 4) is determined using implicit differentiation. Both sides of the equation are differentiated with respect to \(x\).

\(\frac{d}{dx}(x^{5/2})+\frac{d}{dx}(y^{5/2})=\frac{d}{dx}(33)\)

Applying the chain and power rules yields:

\(\frac{5}{2}x^{3/2}+\frac{5}{2}y^{3/2}\frac{dy}{dx}=0\)

Solving for \(\frac{dy}{dx}\) to obtain the tangent's slope:

\(\frac{5}{2}y^{3/2}\frac{dy}{dx}=-\frac{5}{2}x^{3/2}\)

\(\frac{dy}{dx}=-\frac{x^{3/2}}{y^{3/2}}\)

Substituting \(x=1\) and \(y=4\) into the derivative gives the slope at (1, 4):

\(\frac{dy}{dx}=-\frac{1^{3/2}}{4^{3/2}}=-\frac{1}{8}\)

Using the point-slope form of a line, \(y-y_1=m(x-x_1)\), with slope \(-\frac{1}{8}\) at (1, 4):

\(y-4=-\frac{1}{8}(x-1)\)

Simplifying the equation:

\(y-4=-\frac{1}{8}x+\frac{1}{8}\)

Multiplying by 8 to eliminate fractions:

\(8y-32=-x+1\)

Rearranging terms to form the final equation:

\(x+8y-33=0\)

The equation of the tangent to the curve at point (1, 4) is \(x+8y-33=0\).

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