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If f(x) = 3x + 6, then find f -1(x). Solution: y=3x+6; swap y and x: x=3y+6; solve for y: y=(x-6)/3, and f-1(x)=(x-6)/3
Determine if the following functions are inverses of each other: f(x) = 7x + 14 g(x) = (1/7)x - 2 Solution: Find composite (fog)(x)= 7((1/7)x - 2) + 14=x-14+14=x - yes these functions are inverse
Write the exponential equation y = 3x in logarithmic form. Solution: log y= log 3x = x log 3 or log3 y= log33x = x log3 3=x i.e. log3 y=x
Write the logarithmic equation log7x = y in exponential form. Solution: x = 7y
Use the change-of-base formula to convert x=log480 to common logarithms. Then use a calculator to round the value of x to the nearest thousandth. Solution: x=log480= log80/log4= 1.903/0.602=3.161
Find the amount of money accumulated if you invest $40,000 at 6% interest compounded quarterly for 5 years. Round your answer to the nearest cent. Solution: A=P(1+r/n)nt i.e. A=$40000*(1+0.06/4)4*5 = $40,000*1.282=$51,281.49
Find the amount of money accumulated if you invest $40,000 at 6% interest compounded continuously for 5 years. Round your answer to the nearest cent. Solution: A=P*exp(rt)= $40,000*exp(0.06*5)=$40,000*1.35=$53,994.35
Solve the following exponential equation: 5x = 2 Round your solution to the nearest hundredth. Solution: apply log to both sides log5x = log 2 or x*log5=log2 and x= log2/log 5=0.301/0.699=0.431
Solve the following exponential equation: e2x = 18 Round your solution to the nearest hundredth. Solution: apply natural log to both sides 2x=ln 18 or x=1/2*ln18=2.89/2=1.445
Solve the following logarithmic equation: log5x + log5(4x+5) = 3 Be sure to check all of your solutions in the original equation. Solution: log5x(4x+5) = log5 53 or x(4x+5)=125 i.e 4x2 +5x-125=0 using quadratic formula: x=5 and x=? - let you practice your quadratic formula skills