Introduction to Electric Circuits, 9th Edition

APPENDIX C

Mathematical Formulas

C.1 Trigonometric Identities

1. sin ( −α) = −sin α
2. cos ( −α) = cos α
3. sin α = cos (α − 90°) = −cos (α + 90°)
4. cos α = −sin (α − 90°) = sin (α + 90°)
5. sin α = −sin (α ± 180°)
6. cos α = −cos (α ± 180°)
7. sin (α ± β) = sin α cos β ± cos α sin β
8. 
9. 
10. sin 2α = 2 sin α cos α
11. cos 2α = cos²α − sin²α
12. 2 sin α sin β = cos (α − β) − cos (α + β)
13. 2 sin α cos β = sin (α + β) + sin (α − β)
14. 2 cos α cos β = cos (α + β) + cos (α − β)
15. 2 sin²α = 1 − cos 2α
16. 2 cos²α = 1 + cos 2α
17. sin²α + cos²α = 1

C.2 Derivatives

The letters u and v represent functions of x, whereas a, b, and m are constants.

1. 
2. 
3. 
4. 
5. 

C.3 Indefinite Integrals

The letters u and v represent functions of x, whereas a and b are constants. ...