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sin 2θ = 2(sin θ)(cos θ)
cos 2θ = (cos θ)2 - (sin θ)2
cos 2θ = 2(cos θ)2 - 1
cos 2θ = 1 - 2(sin θ)2
tan 2θ = 2(tan θ)/[1 - (tan θ)2]
sin θ/2 = ±√[(1 - (cos θ))/2]
cos θ/2 = ±√[(1 + (cos θ))/2]
tan θ/2 = ±√[(1 - (cos θ))/(1 + (cos θ))] ; cos θ ≠ -1
tan θ/2 = [1 - (cos θ)]/(sin θ)
tan θ/2 = (sin θ)/[1 + (cos θ)]
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How do you simplify trigonometric expressions?
Use the trigonometric relations and identities.
Can you help me prove math trig identities?
these are the identities i need sinΘcosΘ=cosΘ sec^4Θ-tan^4Θ=sec²Θcsc²Θ (1+sec²Θ)/(1-secΘ)=(cosΘ-1)/(cosΘ)
What is the term trigonometry identity?
Trigonometric identities are trigonometric equations that are always true.
What does trigonometric identities all about?
They are true statements about trigonometric ratios and their relationships irrespective of the value of the angle.
What are five trigonometric identities?
All others can be derived from these and a little calculus: sin2x+cos2x=1 sec2x-tan2x=1 sin(a+b)=sin(a)cos(b)+sin(b)sin(a) cos(a+b)=cos(a)cos(b)-sin(a)sin(b) eix=cos(x)+i*sin(x)
