HP 40gs User Manual page 225

TLIN
TRIG
Computer Algebra System (CAS)
gives:
3
4·cos(x) –3·cos(x)
Linearize a trigonometric expression
TLIN has as an argument a trigonometric expression.
TLIN linearizes this expression in terms of sin(n x) and
cos(n x).
Example 1
Typing:
TLIN(COS(X) · COS(Y))
gives:
1
⋅ ( )
-- -
cos x y –
2
Example 2
Typing:
TLIN(COS(X)
gives:
1
⋅ ( 3 x ⋅ )
-- -
cos +
4
Example 3
Typing:
TLIN(4·COS(X)
gives:
⋅ ( 2 x ⋅ )
2 cos
Simplify using sin(x)
TRIG has as an argument a trigonometric expression.
TRIG simplifies this expression using the identity
2 2
sin(x) + cos(x) = 1.
1
⋅ ( )
-- -
+ cos x + y
2
3
)
3
⋅ x ( )
-- -
cos
4
2
-2)
2
+ cos(x)
2
= 1
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