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View Full Version : sec(2x)=3cos(2x)+cos(90^0 - 2x), find x


handi
Jan 20, 2013, 11:00 PM
solve the following equation in the given interval : sec

ebaines
Jan 22, 2013, 08:02 AM
Hint: start by converting the sec(2x) to 1/cos(2x), and the cos(90-2x) to sin(2x). Then I suggest put the sin(2x) term into sqrt(1-cos^2(2x)), rearrange and solve for cos(2x).