Step 1 :Simplify the expression inside the limit
Step 2 :\(\frac{\cos^{-1}\left(\frac{3}{5}+h\right)-\cos^{-1}\left(\frac{3}{5}\right)}{h}\)
Step 3 :Apply the identity \(\cos^{-1}(a) - \cos^{-1}(b) = \cos^{-1}(a\sqrt{1-b^2} + b\sqrt{1-a^2})\)
Step 4 :\(\frac{\cos^{-1}\left(\frac{3}{5}\sqrt{1-\left(\frac{3}{5}+h\right)^2}+\left(\frac{3}{5}+h\right)\sqrt{1-\left(\frac{3}{5}\right)^2}\right)}{h}\)
Step 5 :Simplify the expression inside the inverse cosine function
Step 6 :\(\frac{\cos^{-1}\left(\frac{3}{5}\sqrt{\frac{16}{25}-\frac{6h}{5}-h^2}+\frac{3}{5}\sqrt{\frac{16}{25}}+\frac{3}{5}h\right)}{h}\)
Step 7 :Evaluate the limit as \(h\) approaches 0
Step 8 :\(\lim _{h \rightarrow 0} \frac{\cos^{-1}\left(\frac{3}{5}\sqrt{\frac{16}{25}-\frac{6h}{5}-h^2}+\frac{3}{5}\sqrt{\frac{16}{25}}+\frac{3}{5}h\right)}{h}\)
Step 9 :Apply the derivative of the inverse cosine function
Step 10 :\(\lim _{h \rightarrow 0} -\frac{1}{\sqrt{1-\left(\frac{3}{5}\sqrt{\frac{16}{25}-\frac{6h}{5}-h^2}+\frac{3}{5}\sqrt{\frac{16}{25}}+\frac{3}{5}h\right)^2}}\)
Step 11 :Evaluate the limit as \(h\) approaches 0
Step 12 :\(\lim _{h \rightarrow 0} -\frac{1}{\sqrt{1-\left(\frac{3}{5}\sqrt{\frac{16}{25}}\right)^2}}\)
Step 13 :Simplify the expression
Step 14 :\(\lim _{h \rightarrow 0} -\frac{1}{\sqrt{1-\frac{9}{25}}}\)
Step 15 :Evaluate the limit
Step 16 :\(\lim _{h \rightarrow 0} -\frac{1}{\frac{4}{5}}\)
Step 17 :Simplify the expression
Step 18 :\(\lim _{h \rightarrow 0} -\frac{5}{4}\)
Step 19 :Final Answer: \(\boxed{-\frac{5}{4}}\)