Calculus Methods

 



You
need at your fingertips the following two-way processes. This table is not intended to introduce you to new ideas, but merely to summarise what you already know.




A xn Differentiation: Move the index round to the front & reduce the index by 1. Leave any multiplicative constants in place
--------------->
nA xn-1
(B/m) xm+1 Integration: Increase the index by 1, and divide any multiplicative constants (including an implied 1 if there are no others) by the increased index.
<---------------
B xm



A sin(kx)

A cos(kx)
Differentiation: Change sin() to cos() [or cos() to - sin()]. Pre-multiply by the coefficient of x that is within the sin() or cos() function - but do not tinker with the version of the cooefficient that is actually inside the sin or cos bracket.
--------------->
kA cos(kx)

- kA sin(kx)
(B/k) sin(kx)

- (B/k) cos(kx)
Integration: Change cos() to sin() [or sin() to -cos()]. Divide by the coefficient of x that is within the sin() or cos() function - but do not tinker with the version of the cooefficient that is actually inside the sin or cos bracket.
<---------------
B cos(kx)

B sin(kx)



A ekx Differentiation: Pre-multiply by the coefficient of x that is in the exponent - but do not tinker with the version of the cooefficient that is actually in the exponent. Make no other changes, since the exponential function is essentially its own differential coefficient.
--------------->
kA ekx
(B/k) ekx Integration: Divide by the coefficient of x that is in the exponent - but do not tinker with the version of the cooefficient that is actually in the exponent. Make no other changes, since the exponential function is essentially its own integral.
<---------------
B ekx



A ln(kx) Differentiation: Notice that the k vanishes. This is because  ln(kx) may be split up as  ln(k) + ln(x), the first term of which is a constant.
--------------->
A (1/x)
B ln(x)

[ = ln(
xB) ]
Integration: This is a special case. Make sure that any coefficients of x are bundled up in B before carrying out the integration. You may or may not want to convert the answer to the form in [ ].
<---------------
B (1/x)





Some tips for integrating: