Examples of Math Problems: The variables x and y satisfy the equation y=A(b^-x), where A and b are constants. The graph of ln y against x is a straight line passing through the points (0, 1.3) and (1.6, 0.9). Find the values of A and b, correct to 2 decimal places.

Wednesday, May 21, 2014

The variables x and y satisfy the equation y=A(b^-x), where A and b are constants. The graph of ln y against x is a straight line passing through the points (0, 1.3) and (1.6, 0.9). Find the values of A and b, correct to 2 decimal places.

y=A%2Fb%5Ex

1.3=A%2Fb%5E0

A=1.30

so this means
0.9=1.3%2Fb%5E1.6

0.9=1.3%2Fb%5E1.6

and so

b=1.26

y=1.30%2F1.26%5Ex

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