Saturday

February 28, 2015

February 28, 2015

Posted by **xX_Supaman_Xx** on Sunday, December 2, 2007 at 6:12pm.

sin(c+h)=sin(c)xcos(h)+cos(c)xsin(h)

but how?

please explain

- Reposted: Maths - Trig -
**drwls**, Sunday, December 2, 2007 at 6:31pmHere you will find a proof of that trigonometric identity:

http://library.thinkquest.org/C0110248/trigonometry/formsine.htm

- Reposted: Maths - Trig -
**Reiny**, Sunday, December 2, 2007 at 6:56pmHere is another approach to the proof

http://www.themathpage.com/aTrig/sum-proof.htm

(there seems to be a 'spacing' problem in the html code in the first few lines, but I am sure you know what the equation should read )

**Answer this Question**

**Related Questions**

Maths-Trig - How does sin(c+h)=sin(c)xcos(h)+cos(c)xsin(h) please explain

TRIG! - Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6...

trig - The expression 4 sin x cos x is equivalent to which of the following? (...

trig - Reduce the following to the sine or cosine of one angle: (i) sin145*cos75...

Mathematics - Trigonometric Identities - Let y represent theta Prove: 1 + 1/tan^...

algebra - Can someone please help me do this problem? That would be great! ...

tigonometry - expres the following as sums and differences of sines or cosines ...

Math - Calculus - The identity below is significant because it relates 3 ...

Trig - Given: cos u = 3/5; 0 < u < pi/2 cos v = 5/13; 3pi/2 < v < ...

pre calc trig check my work please - sin x + cos x -------------- = ? sin x sin ...