Q. Given the substitutions ln2=a,ln3=b, and ln5=c, find the value of ln(45) in terms of a,b, and c.Answer:
Breakdown using properties: We need to express ln(45) in terms of a, b, and c. We can start by using the properties of logarithms to break down ln(45) into simpler parts that involve ln(2) and ln(5).ln(45)=ln(4)+ln(5)
Express ln(4): We know that 4 is 2 squared, so ln(4) can be written as ln(22). Using the power rule for logarithms, which states that ln(xy)=y⋅ln(x), we get:ln(4)=ln(22)=2⋅ln(2)Since ln(2)=a, we can substitute a for ln(2):40
Express ln(5): Next, we look at ln(5). The square root of 5 is the same as 5 raised to the 21 power. Using the power rule for logarithms again, we get:ln(5)=ln(521)=(21)⋅ln(5)Since ln(5)=c, we can substitute c for ln(5):ln(5)=(21)⋅c
Combine results: Now we can combine our results for ln(4) and ln(5) to find ln(45):ln(45)=ln(4)+ln(5)=2⋅a+(21)⋅c
Final expression: We have successfully expressed ln(45) in terms of a and c. There is no need to include b in our expression because it does not appear in the original problem.
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