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#### karush

##### Well-known member

- Jan 31, 2012

- 3,084

The deflection \(\displaystyle D\) of a beam of length \(\displaystyle L\) is

\(\displaystyle D=2x^4-5Lx^3+3L^2x^2\),

where \(\displaystyle x\) is the distance from one end of the beam.

Find the value of \(\displaystyle x\) that yields the maximum deflection

The answer to this is \(\displaystyle x=\Bigg(\frac{15-\sqrt{33}}{16}\Bigg)L \approx 0.578L\)

well first of all this equation has 2 variables in x and L so not sure what to do perhaps implicit differentiation. also the answer looks it came from a quadratic formula

so not to sure what the first step is.