hp40g+.book Page 42 Friday, December 9, 2005 1:03 AM

TCOLLECT linearizes this expression in terms of sin(n x) and cos(n x), then (in Real mode) reconstructs the sine and cosine of the same angle.

 

Typing:

 

 

 

TCOLLECT(SIN(X) + COS(X))

 

gives:

 

 

 

2 ⋅ cos

⎛

π⎞

 

⎝

x – --

 

 

4⎠

TEXPAND

Develop transcendental expressions

TEXPAND has as an argument a transcendental expression (that is, an expression with trigonometric, exponential or logarithmic functions). TEXPAND develops this expression in terms of sin(x), cos(x), exp(x) or ln(x).

Example 1

Typing:

TEXPAND(EXP(X+Y))

gives:

exp(x)·exp(y)

Example 2

Typing:

TEXPAND(LN(X·Y))

gives:

ln(y) + ln(x)

Example 3

Typing:

TEXPAND(COS(X+Y))

gives:

cos(y)·cos(x)–sin(y)·sin(x)

Example 4

Typing:

TEXPAND(COS(3·X))

14-42

 

 

Computer Algebra System (CAS)