MathDB
Graph rotation

Source: AHSME 1991 problem 24

October 30, 2011
geometrygeometric transformationrotationlogarithmsAMC

Problem Statement

The graph, GG of y=log⁡10xy = \log_{10}x is rotated 90∘90^{\circ} counter-clockwise about the origin to obtain a new graph G′G'. Which of the following is an equation for G′G'?
<spanclass=′latex−bold′>(A)</span> y=log⁡10(x+909)<spanclass=′latex−bold′>(B)</span> y=log⁡x10<spanclass=′latex−bold′>(C)</span> y=1x+1<spanclass=′latex−bold′>(D)</span> y=10−x<spanclass=′latex−bold′>(E)</span> y=10x <span class='latex-bold'>(A)</span>\ y = \log_{10}\left(\frac{x + 90}{9}\right)\qquad<span class='latex-bold'>(B)</span>\ y = \log_{x}10\qquad<span class='latex-bold'>(C)</span>\ y = \frac{1}{x + 1}\qquad<span class='latex-bold'>(D)</span>\ y = 10^{-x}\qquad<span class='latex-bold'>(E)</span>\ y = 10^{x}
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