Trigonometric formulae for ""CLASS 11th""
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Periodic Identity of Trigonometric Angles:
sin (π/2 – A) = cos A & cos (π/2 – A) = sin A
sin (π/2 + A) = cos A & cos (π/2 + A) = – sin A
sin (3π/2 – A) = – cos A & cos (3π/2 – A) = – sin A
sin (3π/2 + A) = – cos A & cos (3π/2 + A) = sin A
sin (π – A) = sin A & cos (π – A) = – cos A
sin (π + A) = – sin A & cos (π + A) = – cos A
sin (2π – A) = – sin A & cos (2π – A) = cos A
sin (2π + A) = sinA cos (2π + A) = cos A
Cofunction Identity:
sin(90°− x) = cos x
cos(90°− x) = sin x
tan(90°− x) = cot x
cot(90°− x) = tan x
sec(90°− x) = cosec x
cosec(90°− x) = sec x
Sum and Difference Trigonometric Formula:
sin(x + y) = sin(x)cos(y) + cos(x)sin(y)
cos(x + y) = cos(x)cos(y) – sin(x)sin(y)
tan(x + y) = (tan x + tan y)/(1 − tan x • tan y)
sin(x – y) = sin(x)cos(y) – cos(x)sin(y)
cos(x – y) = cos(x)cos(y) + sin(x)sin(y)
tan(x − y) = (tan x – tan y)/(1 + tan x • tan y)
Double Angle Formula:
sin(2x) = 2sin(x) • cos(x) = [2tan x/(1 + tan2x)]
cos(2x) = cos2(x) – sin2(x) = [(1 - tan2x)/(1 + tan2x)]
cos(2x) = 2cos2(x) − 1 = 1 – 2sin2(x)
tan(2x) = [2tan(x)]/ [1−tan2(x)]
sec (2x) = sec2 x/(2 - sec2 x)
csc (2x) = (sec x. csc x)/2
Inverse Trigonometric Function:
sin-1 (–x) = – sin-1 x
cos-1 (–x) = π – cos-1 x
tan-1 (–x) = – tan-1 x
cosec-1 (–x) = – cosec-1 x
sec-1 (–x) = π – sec-1 x
cot-1 (–x) = π – cot-1 x
[tex]\red{\boxed{\mathfrak\colorbox{grey}{Answer}}}[/tex]
Trigonometry Formulas
sin(−θ) = −sin θ
cos(−θ) = cos θ
tan(−θ) = −tan θ
cosec(−θ) = −cosecθ
sec(−θ) = sec θ
cot(−θ) = −cot θ
Product to Sum Formulas
sin x sin y = 1/2 [cos(x–y) − cos(x+y)]
cos x cos y = 1/2[cos(x–y) + cos(x+y)]
sin x cos y = 1/2[sin(x+y) + sin(x−y)]
cos x sin y = 1/2[sin(x+y) – sin(x−y)]
Sum to Product Formulas
sin x + sin y = 2 sin [(x+y)/2] cos [(x-y)/2]
sin x – sin y = 2 cos [(x+y)/2] sin [(x-y)/2]
cos x + cos y = 2 cos [(x+y)/2] cos [(x-y)/2]
cos x – cos y = -2 sin [(x+y)/2] sin [(x-y)/2]
Identities
sin2 A + cos2 A = 1
1+tan2 A = sec2 A
1+cot2 A = cosec2 A
[tex]\red{\boxed{\mathfrak\colorbox{grey}{Answer}}}[/tex]
Trigonometry Formulas
sin(−θ) = −sin θ
cos(−θ) = cos θ
tan(−θ) = −tan θ
cosec(−θ) = −cosecθ
sec(−θ) = sec θ
cot(−θ) = −cot θ
Product to Sum Formulas
sin x sin y = 1/2 [cos(x–y) − cos(x+y)]
cos x cos y = 1/2[cos(x–y) + cos(x+y)]
sin x cos y = 1/2[sin(x+y) + sin(x−y)]
cos x sin y = 1/2[sin(x+y) – sin(x−y)]
Sum to Product Formulas
sin x + sin y = 2 sin [(x+y)/2] cos [(x-y)/2]
sin x – sin y = 2 cos [(x+y)/2] sin [(x-y)/2]
cos x + cos y = 2 cos [(x+y)/2] cos [(x-y)/2]
cos x – cos y = -2 sin [(x+y)/2] sin [(x-y)/2]
Identities
sin2 A + cos2 A = 1
1+tan2 A = sec2 A
1+cot2 A = cosec2 A
[tex]\red{\boxed{\mathfrak\colorbox{grey}{Answer}}}[/tex]
Trigonometry Formulas
sin(−θ) = −sin θ
cos(−θ) = cos θ
tan(−θ) = −tan θ
cosec(−θ) = −cosecθ
sec(−θ) = sec θ
cot(−θ) = −cot θ
Product to Sum Formulas
sin x sin y = 1/2 [cos(x–y) − cos(x+y)]
cos x cos y = 1/2[cos(x–y) + cos(x+y)]
sin x cos y = 1/2[sin(x+y) + sin(x−y)]
cos x sin y = 1/2[sin(x+y) – sin(x−y)]
Sum to Product Formulas
sin x + sin y = 2 sin [(x+y)/2] cos [(x-y)/2]
sin x – sin y = 2 cos [(x+y)/2] sin [(x-y)/2]
cos x + cos y = 2 cos [(x+y)/2] cos [(x-y)/2]
cos x – cos y = -2 sin [(x+y)/2] sin [(x-y)/2]
Identities
sin2 A + cos2 A = 1
1+tan2 A = sec2 A
1+cot2 A = cosec2 A