hi, my question is from Modern Engineering Mathematics by Glyn James(adsbygoogle = window.adsbygoogle || []).push({});

pg 177 # 17a

Using the exponential forms of cos(theta) and sin(theta) given in (3.11a, b), prove the following trigonometric identities:

a) sin(x + y) = sin(x)cos(y) + cos(x)sin(y)

and 3.11a is:

cos(x) = 0.5*[ e^(jx) + e^(-jx) ] where x= theta

and 3.11b is:

sin(x) = 0.5j*[ e^(jx) - e^(-jx) ] where x= theta

i've gotten to the point where i have

[ e^j(x+y) + e^j(x-y) -e^j(y-x) -e^-j(x + y) ] / 2j

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# Homework Help: Exponential forms of cos and sin

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