Question

prove that

(sinA)/1+cosA = tan(1/2)A

I can't seem to see it? ><

Answer 1

hint1 : sin(A) = 2sin(A/2) cos(A/2)

Answer 2

hint2 : cosA = 2cos^2(A/2) - 1

Answer 3

just let A = 2X if you want..

Answer 4

ohh so sin/cos i'll end up with

tan(A/2)

Answer 5

Right:
=-=-=-

\[\frac{ sinA }{ CosA + 1 } = \tan(\frac{ 1 }{ 2 } A)\]
\[\frac{ SinA }{ 1+(2Cos^2\frac{ A }{ 2 }) - 1}\]

\[\frac{ SinA }{ 2Cos^2(\frac{ A }{ 2 })}\]

Left:
=-=-=-=
tan(A/2) = \[\frac{ Sin(A/2) }{ Cos(A/2) } * 2Cos(A/2) \]
\[\frac{ 2Sin(A/2)Cos(A/2) }{ 2Cos(A/2)*Cos(A/2) }\]
\[SinA/ 2Cos^2(A/2)\]

Right = left

Answer 6

yeap i got taht

thank you

Answer 7

Fine.You are welcome.

Answer 8

but @TrojanPoem wouldn't it be sinA/2 • cosA/2 and not cos^2A/2?

Answer 9

Specify in which step.