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6.6.3 SPM practice 3 (Linear Law) – Question 3


Question 3
The table below shows the values of two variables, x and y, obtained from an experiment. The variables x and y are related by the equation a y = b x + 1 , where k and p are constants.


(a) Based on the table above, construct a table for the values of 1 x and 1 y . Plot 1 y against 1 x , using a scale of  2 cm to 0.1 unit on the 1 x – axis and  2 cm to 0.2 unit on the 1 y – axis. Hence, draw the line of best fit.
(b) Use the graph from  (b)  to find the value of
(i)  a,
(ii)  b.
Solution
Step 1 : Construct a table consisting X and Y.




Step 2 : Plot a graph of Y against X, using the scale given and draw a line of best fit




Step 3 : Calculate the gradient, m, and the Y-intercept, c, from the graph




Step 4 : Rewrite the original equation given and reduce it to linear form

Step 5 : Compare with the values of m and c obtained, find the values of the unknown required

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