
#1
Feb2812, 03:50 PM

P: 34

Hey guys,
I was hoping somebody might help me; I'm really confused. I obtained the formula for distance, which is this: d=[(2[v_0]^2(cos[alpha])sin([alphabeta])]/gcos^2(beta) And the derivative for distance, which is this: derivative of d with respect to alpha=0=(2[v_0]^2)/(gcos^2(beta))*(sin(alpha)sin(alphabeta)+cos(alpha)cos(alphabeta))*cos(2alphabeta) I was trying to see what alpha would be for maximum range, but I have no idea where the very end term on the right comes from: cos(2alphabeta). Could somebody please me? Thank you. David 



#2
Feb2812, 04:17 PM

Sci Advisor
HW Helper
Thanks
P: 26,167

Hey David!
cos(A+B) = cosAcosB  sinAsinB 



#3
Feb2812, 10:06 PM

P: 34

Thank you very much TinyTim! That was exactly what I needed! :D



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