HP 40gs User Manual page 213

hp40g+.book Page 31 Friday, December 9, 2005 1:03 AM
LNCOLLECT
POWEXPAND
SINCOS
Computer Algebra System (CAS)
1
⋅ – ( ( ⋅ ⋅ ) )
-- -
exp 2 i x + +
4
Example 3
Typing:
LIN(SIN(X))
gives:
i i
-- - ⋅ i x ⋅ -- - ⋅
– exp + exp
2 2
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))
Transform a power
POWEXPAND writes a power in the form of a product.
Typing:
POWEXPAND((X+1)
gives:
(x+1) · (x+1) · (x+1)
This allows you to do the development of (x + 1)
by step, using DISTRIB several times on the preceding
result.
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 1
⋅ ( ⋅ ⋅ )
-- - -- -
exp 2 i x
2 4
– ( ( i x ⋅ ) )
3
)
3
in step
14-31