DERIVATIVE of EXPONENTIAL
GENERAL FORMULA If  y = a x , where  a = constant or any values then  y’ = dy/dx = a x  ln a , where ln is log e Similar with  y = a f(x) then  y’ = dy/dx = a f(x)  ln a f’(x)
PROVING Let y = a x ,  then put ln on both sides ln y = ln a x , ln y = x lna Derify both sides & remember derivative of ln x is 1/x 1/y . dy = 1 . lna . dx then rearrange    dy/dx = y lna dy/dx = a x  lna
Examples Y = 2 x , Y’= 2 x  ln2 Y= 0.5 x , Y’= 0.5 x  ln0.5 Y = 2 x 2 , Y’= 2 x 2  ln2 (2x) Y= 2 -3x , Y’= 2 -3x  ln2 (-3)
Examples 2 Y = b x , Y’= b x  lnb Y= b x 2 -3x , Y’= b x 2 -3x  lnb (2x-3) Y = e x , Y’= e x  lne, Since lne = 1, then Y’ = e x For Y = e x  , then Y’ = e x
Examples 3 Y = e 3x , Y’= e 3x  lne (3) Y’= 3e 3x   Y = e x 2 -3x , Y’= e x 2 -3x  lne (2x-3) Y’=(2x-3)e x 2 -3x

Fri 13jan

  • 1.
  • 2.
    GENERAL FORMULA If y = a x , where a = constant or any values then y’ = dy/dx = a x ln a , where ln is log e Similar with y = a f(x) then y’ = dy/dx = a f(x) ln a f’(x)
  • 3.
    PROVING Let y= a x , then put ln on both sides ln y = ln a x , ln y = x lna Derify both sides & remember derivative of ln x is 1/x 1/y . dy = 1 . lna . dx then rearrange  dy/dx = y lna dy/dx = a x lna
  • 4.
    Examples Y =2 x , Y’= 2 x ln2 Y= 0.5 x , Y’= 0.5 x ln0.5 Y = 2 x 2 , Y’= 2 x 2 ln2 (2x) Y= 2 -3x , Y’= 2 -3x ln2 (-3)
  • 5.
    Examples 2 Y= b x , Y’= b x lnb Y= b x 2 -3x , Y’= b x 2 -3x lnb (2x-3) Y = e x , Y’= e x lne, Since lne = 1, then Y’ = e x For Y = e x , then Y’ = e x
  • 6.
    Examples 3 Y= e 3x , Y’= e 3x lne (3) Y’= 3e 3x Y = e x 2 -3x , Y’= e x 2 -3x lne (2x-3) Y’=(2x-3)e x 2 -3x

Editor's Notes