Find the Derivative: y= ln(sin^2(3.14159(x^1/2))+(cos^2(3.14159x))
C Cronan52 New member Joined Jun 19, 2006 Messages 2 Jun 19, 2006 #1 Find the Derivative: y= ln(sin^2(3.14159(x^1/2))+(cos^2(3.14159x))
skeeter Elite Member Joined Dec 15, 2005 Messages 3,216 Jun 19, 2006 #2 please verify that the given function is ... \(\displaystyle y = ln[sin^2(\pi \sqrt{x}) + cos^2(\pi x)]\)
please verify that the given function is ... \(\displaystyle y = ln[sin^2(\pi \sqrt{x}) + cos^2(\pi x)]\)
skeeter Elite Member Joined Dec 15, 2005 Messages 3,216 Jun 20, 2006 #4 \(\displaystyle \frac{d}{dx} ln(u) = \frac{u'}{u}\) in this case, your "u" is \(\displaystyle sin^2(\pi \sqrt{x}) + cos^2(\pi x)\) just a few applications of the chain rule to find u' ... \(\displaystyle u' = 2sin(\pi \sqrt{x})cos(\pi \sqrt{x}) \frac{\pi}{2\sqrt{x}} - 2cos(\pi x)sin(\pi x)\pi\) \(\displaystyle u' = \frac{\pi}{\sqrt{x}}sin(\pi \sqrt{x})cos(\pi \sqrt{x}) - 2\pi cos(\pi x)sin(\pi x)\) you can finish up with \(\displaystyle \frac{u'}{u}\)
\(\displaystyle \frac{d}{dx} ln(u) = \frac{u'}{u}\) in this case, your "u" is \(\displaystyle sin^2(\pi \sqrt{x}) + cos^2(\pi x)\) just a few applications of the chain rule to find u' ... \(\displaystyle u' = 2sin(\pi \sqrt{x})cos(\pi \sqrt{x}) \frac{\pi}{2\sqrt{x}} - 2cos(\pi x)sin(\pi x)\pi\) \(\displaystyle u' = \frac{\pi}{\sqrt{x}}sin(\pi \sqrt{x})cos(\pi \sqrt{x}) - 2\pi cos(\pi x)sin(\pi x)\) you can finish up with \(\displaystyle \frac{u'}{u}\)