S sbesbesbe Full Member 10+ Year Member Joined Jan 9, 2012 Messages 117 Reaction score 1 Points 4,551 Pre-Dental Aug 20, 2012 #1 Advertisement - Members don't see this ad Hi there SDN I do have a question on QR... sin(2x-30)=cos(4x-60) ... sin(2x-30)=cos(120-2x) BUT why does it become 4x-60=120-2x ? (why is 2x-30 doubled)? please don't laugh if this is supposed to be an easy question...
Advertisement - Members don't see this ad Hi there SDN I do have a question on QR... sin(2x-30)=cos(4x-60) ... sin(2x-30)=cos(120-2x) BUT why does it become 4x-60=120-2x ? (why is 2x-30 doubled)? please don't laugh if this is supposed to be an easy question...
M Mr Dental Full Member 10+ Year Member Joined Feb 17, 2009 Messages 32 Reaction score 0 Points 0 Pre-Dental Aug 20, 2012 #2 Say A=sin(2x-30). Then A=cos(4x-60) and A=cos(120-2x) A=A, so cos(4x-60)=cos(120-2x). cosine on both sides cancel out, so 4x-60=120-2x. Remember, a=b, a=c, then b=c. Upvote 0 Downvote
Say A=sin(2x-30). Then A=cos(4x-60) and A=cos(120-2x) A=A, so cos(4x-60)=cos(120-2x). cosine on both sides cancel out, so 4x-60=120-2x. Remember, a=b, a=c, then b=c.
Troyvdg Dentistry not Debtistry 15+ Year Member Joined Jul 13, 2009 Messages 788 Reaction score 191 Points 5,241 Location Bay Area Pre-Dental Aug 20, 2012 #3 EDIT: someone just posted before me Upvote 0 Downvote
S sbesbesbe Full Member 10+ Year Member Joined Jan 9, 2012 Messages 117 Reaction score 1 Points 4,551 Pre-Dental Aug 20, 2012 #4 Mr Dental said: Say A=sin(2x-30). Then A=cos(4x-60) and A=cos(120-2x) A=A, so cos(4x-60)=cos(120-2x). cosine on both sides cancel out, so 4x-60=120-2x. Remember, a=b, a=c, then b=c. Click to expand... thanks a lot! Upvote 0 Downvote
Mr Dental said: Say A=sin(2x-30). Then A=cos(4x-60) and A=cos(120-2x) A=A, so cos(4x-60)=cos(120-2x). cosine on both sides cancel out, so 4x-60=120-2x. Remember, a=b, a=c, then b=c. Click to expand... thanks a lot!
