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#1 2013-09-08 16:37:40

shivusuja
Member
Registered: 2006-09-14
Posts: 56

Trignometry

please help me out

IF  a sin x +b cos x = c . Prove that     a cos – b sinx=sq root(a sqared+b squared+c squared)

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#2 2013-09-08 19:05:36

bob bundy
Moderator
Registered: 2010-06-20
Posts: 6,313

Re: Trignometry

hi shivusuja

where

Do a similar thing with the second expression leading to cos(x + alpha)

Now you can use sin^2 + cos^2 = 1 to finish the proof.

Note: But I ended up with minus c^2 not plus.

Bob


You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#3 2013-09-09 02:27:26

shivusuja
Member
Registered: 2006-09-14
Posts: 56

Re: Trignometry

thank you . may be the text book print is wrong.

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