HP 40gs User Manual
Page 213
Computer Algebra System (CAS)
14-31
Example 3
Typing:
LIN(SIN(X))
gives:
LNCOLLECT
Regroup the logarithms
LNCOLLECT has as an argument an expression
containing logarithms.
LNCOLLECT regroups the terms in the logarithms. It is
therefore preferable to use an expression that has already
been factored (using
FACTOR).
Typing:
LNCOLLECT(LN(X+1)+LN(X-1))
gives:
ln((x+1)(x−1))
POWEXPAND
Transform a power
POWEXPAND writes a power in the form of a product.
Typing:
POWEXPAND((X+1)
3
)
gives:
(x+1) · (x+1) · (x+1)
This allows you to do the development of (x + 1)
3
in step
by step, using
DISTRIB several times on the preceding
result.
SINCOS
Transform the complex exponentials into sin and cos
SINCOS takes as an argument an expression containing
complex exponentials.
SINCOS then rewrites this expression in terms of sin(x)
and cos(x).
1
4
---
2 i x
⋅ ⋅
(
)
–
(
)
exp
⋅
1
2
--- 1
4
---
2 i x
⋅ ⋅
(
)
exp
⋅
+ +
i
2
---
i x
⋅
exp
⋅
i
2
---
i x
⋅
(
)
–
(
)
exp
⋅
+
–
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