document.write( "Question 1163697: unsolved 2020-08-22 10:07:30 It is believed that two quantities, z and d are Connected by the relationship of the form z=kd^n where k and n are provided that d doesn't exceed some fixed (but unknown)values D.An experiment produced the following data
\n" ); document.write( "D 750 810 870 930 990 1050 1110 1170
\n" ); document.write( "Z 2.1 2.6 3.2 4.0 4.8 5.6 5.9 6.1
\n" ); document.write( "a)Plot the values of log10Z against log10 d.Use these points to suggest a
\n" ); document.write( "value for D.
\n" ); document.write( "b)It is known tht for d < D,n is a whole number.Use your graph to find the value of n.Show also that k=5×10^-9
\n" ); document.write( "c) Use your value of n and the estimate k=5×10^-9 to find the value of d for which z=3.0.
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Algebra.Com's Answer #853915 by KMST(5342)\"\" \"About 
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If \"z=k%2Ad%5En\" , then \"log%2810%2Cz%29=log%2810%2Ck%29%2Bn%2Alog%2810%2Cd%29\"
\n" ); document.write( "The graph of \"log%2810%2Cz%29\" against \"log%2810%2Cd%29\" would be expected to be a straight line with slope \"n\" up to a certain value \"log%2810%2Cd%29=log%2810%2CD%29\" .
\n" ); document.write( "We need to calculate and tabulate \"log%2810%2Cz%29\" and \"log%2810%2Cd%29\"
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\n" ); document.write( "a)Then we plot \"log%2810%2Cz%29\" against \"log%2810%2Cd%29\"
\n" ); document.write( " The points in green, up to \"log%2810%2Cd%29=3.021\" , corresponding to \"d=1050\" fit well enough on a line. That supports suggesting \"highlight%28D=1050%29\" .
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\n" ); document.write( "b) We could estimate \"n\" as the slope between points \"%22%28%22\"\"log%2810%2Cd%29\"\"%22%2C%22\"\"log%2810%2Cz%29\"\"%22%29%22\" \"%22%28%22\"\"2.875\"\"%22%2C%22\"\"0.3222\"\"%22%29%22\" and \"%22%28%22\"\"3.021\"\"%22%2C%22\"\"0.7482\"\"%22%29%22\"
\n" ); document.write( "That slope is \"%280.7482-0.3222%29%2F%283.021-2.875%29=0.4260%2F0.146=2.92%28%22rounded%22%29\"
\n" ); document.write( "Since \"n\" is supposed to be a whole number, it must be \"highlight%28n=3%29\".\r
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\n" ); document.write( "\n" ); document.write( "c) For \"k=5%C3%9710%5E-9\" \"log%2810%2Ck%29=log%2810%2C5%2A10%5E-9%29=-8.30103\" (rounded)\r
\n" ); document.write( "\n" ); document.write( "Substituting values for \"z=3.0\" , \"n=3\" \"k=5%C3%9710%5E-9\", with \"log%2810%2Ck%29=-8.30103%0D%0A\" and \"log%2810%2C3%29=0.47712\" into \"log%2810%2Cz%29=log%2810%2Ck%29%2Bn%2Alog%2810%2Cd%29\" we get
\n" ); document.write( "\"0.47712=-8.30103%2B3log%2810%2Cd%29\"
\n" ); document.write( "\"0.47712%2B8.30103=3log%2810%2Cd%29\"
\n" ); document.write( "\"8.77815=3log%2810%2Cd%29\"
\n" ); document.write( "\"8.77815%2F3=log%2810%2Cd%29\"
\n" ); document.write( "\"2.92615=log%2810%2Cd%29\"
\n" ); document.write( "\"d=10%5E2.92615\" to get \"highlight%28d=843%29\" as the value of d for which z=3.0.
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