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Mathematics 7 Online
OpenStudy (anonymous):

Please help..:)

OpenStudy (anonymous):

) Show that the equation sin(x−60◦) −cos(30◦−x) = 1 can be written in the form cosx = k, where k is a constant.

OpenStudy (anonymous):

@Callisto @ganeshie8 @robtobey

OpenStudy (callisto):

* All angles are in degrees. Left side = sin(x−60) −cos(30−x) = cos[90-(x-60)] - cos (30-x) = cos (150 - x) - cos (30-x) By cos a - cos b = -2 sin [(a+b)/2)] sin [ (a-b) /2 ] You can reduce the left in -2cosx + (a constant). Will you try?

OpenStudy (anonymous):

cos a - cos b = -2 sin [(a+b)/2)] sin [ (a-b) /2 ]? hw is this possible

OpenStudy (anonymous):

can u expand sin(x-60) = sinxcos60- cosxsin60 and then do it

OpenStudy (callisto):

That would be very time-consuming..

OpenStudy (callisto):

Proof of cos a - cos b = -2 sin [(a+b)/2)] sin [ (a-b) /2 ] ********************************************************* cos(A+B) = cosAcosB - sinAsinB ---(1) cos(A-B) = cosAcosB + sinAsinB ---(2) (1)-(2) cos(A+B) - cos(A-B) = -2sinAsinB Let a = A+B and b = A-B A = (a+b)/2) and B = (a-b)/2 Sub. a = A+B and b = A-B into cos(A+B) - cos(A-B) = -2sinAsinB, we get cos a - cos b = -2sin [(a+b)/2] sin [(a-b)/2],

OpenStudy (anonymous):

thnks

OpenStudy (anonymous):

thanks alot again

OpenStudy (anonymous):

cn u help me with integration problem

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