B bchang57 Full Member 10+ Year Member Joined Jun 13, 2009 Messages 59 Reaction score 0 Points 0 Pre-Dental Mar 4, 2012 #1 Advertisement - Members don't see this ad (sin²θ+cos²θ😉(sin²θ-cos²θ😉/sin2θ I know sin2θ = 2sinθcosθ...but i am stuck -.- i'm trying to get to -cos2θ/sin2θ to get the final answer choice of -cot2θ
Advertisement - Members don't see this ad (sin²θ+cos²θ😉(sin²θ-cos²θ😉/sin2θ I know sin2θ = 2sinθcosθ...but i am stuck -.- i'm trying to get to -cos2θ/sin2θ to get the final answer choice of -cot2θ
N Neil45 Member 10+ Year Member 7+ Year Member 15+ Year Member Joined Oct 20, 2005 Messages 247 Reaction score 0 Points 0 Pre-Health (Field Undecided) Mar 4, 2012 #2 bchang57 said: (sin²θ+cos²θ😉(sin²θ-cos²θ😉/sin2θ I know sin2θ = 2sinθcosθ...but i am stuck -.- i'm trying to get to -cos2θ/sin2θ to get the final answer choice of -cot2θ Click to expand... We know the following: sin²θ+cos²θ = 1 and cos 2θ = cos²θ - sin²θ So to solve the problem: (sin²θ+cos²θ😉(sin²θ-cos²θ😉 / sin2θ (1)(sin²θ-cos²θ😉 / sin2θ - (1)(cos²θ-sin²θ😉 / sin2θ - cos2θ /sin2θ = -cot2θ Upvote 0 Downvote
bchang57 said: (sin²θ+cos²θ😉(sin²θ-cos²θ😉/sin2θ I know sin2θ = 2sinθcosθ...but i am stuck -.- i'm trying to get to -cos2θ/sin2θ to get the final answer choice of -cot2θ Click to expand... We know the following: sin²θ+cos²θ = 1 and cos 2θ = cos²θ - sin²θ So to solve the problem: (sin²θ+cos²θ😉(sin²θ-cos²θ😉 / sin2θ (1)(sin²θ-cos²θ😉 / sin2θ - (1)(cos²θ-sin²θ😉 / sin2θ - cos2θ /sin2θ = -cot2θ
B bchang57 Full Member 10+ Year Member Joined Jun 13, 2009 Messages 59 Reaction score 0 Points 0 Pre-Dental Mar 5, 2012 #3 cos 2θ = cos²θ - sin²θ ahh thank u...a trig identity missing from my brain! Upvote 0 Downvote
