Find $\lim _ { h \rightarrow 0 } \frac { \ln \left( ( x + h ) ^ { 2 } y \right) - \ln \left( x ^ { 2 } y \right) } { h }$

Q18: Let <span class="ql-formula" data-value="z =

Q19: Let the temperature in a flat

Q20: Find the directional derivative of the

Q21: Find the points on the hyperboloid

Q22: Evaluate <span class="ql-formula" data-value="\lim _

Q24: Find the local maximum and minimum

Q25: Let <span class="ql-formula" data-value="z =

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Q28: Find an equation of the tangent