HP 40gs - Manual (Page 222)

14-40 Computer Algebra System (CAS)
Typing:
ATAN2S(ATAN(X))
gives:
HALFTAN Transform in terms of tan(x/2)
HALFTAN has a trigonometric expression as an
argument.
HALFTAN transforms sin(x), cos(x) and tan(x) in the
expression, rewriting them in terms of tan(x/2).
Typing:
HALFTAN(SIN(X) 2 + COS(X) 2 )
gives (SQ(X) = X
2
):
or, after simplification:
1
SINCOS Transform the complex exponentials into sin and cos
SINCOS takes an expression containing complex
exponentials as an argument.
SINCOS then rewrites this expression in terms of sin(x)
and cos(x).
Typing:
SINCOS(EXP(i · X))
gives after turning on complex mode, if necessary:
cos(x) + i · sin(x)
TAN2CS2 Transform tan(x) with sin(2x) and cos(2x)
TAN2CS2 has a trigonometric expression as an
argument.
x
x
2
1 +
------------------
⎝ ⎠
⎜ ⎟
⎛ ⎞
asin
2
x
2
---
⎝ ⎠
⎛ ⎞
tan ⋅
SQ
x
2
---
⎝ ⎠
⎛ ⎞
tan
⎝ ⎠
⎛ ⎞ 1
+
---------------------------------------
⎝ ⎠
⎜ ⎟
⎜ ⎟
⎜ ⎟
⎛ ⎞
2
1 SQ
x
2
---
⎝ ⎠
⎛ ⎞
tan
⎝ ⎠
⎛ ⎞
–
SQ
x
2
---
⎝ ⎠
⎛ ⎞
tan
⎝ ⎠
⎛ ⎞ 1
+
---------------------------------------
⎝ ⎠
⎜ ⎟
⎜ ⎟
⎜ ⎟
⎛ ⎞
2
+
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