Page 22 - Bahan Ajar Bismillah(2)
P. 22
Misal: = 5 sin → = 5 cos
′
′
= → = −
′ − ′
′
=
2
5 cos ∙ cos − 5 sin ∙ −sin
=
2
cos
2
2
5 cos + 5 sin
=
2
cos
2
2
5 (cos + sin )
=
2
cos
5 (1)
=
2
cos
5
=
2
cos
2
= 5 sec
1
′
3. Carilah dan nilai jika diketahui = sec .
3
′
3
Penyelesaian
3
= sec
2
( ) = 3 + ∙
′
3
1 1 1 1 1 1
2
3
′
( ) = 3( ) ( ) + ( ) ( ) ∙ ( )
3 3 3 3 3 3
1 1
2
3
= ∙ 2 + ∙ 2 ∙ 3
3 27
2 2
2
3
= + 3
3 27
18 | P a g e K E L A S X I
