Question

cos x = cos60° cos30°+sin60°sin30° . find x​

Answer 1

Answer:

$\cos(x) = \cos(60) \cos(30) + \sin(60) \sin(30)$

,

$according \: to \: the \: formulae$

$\cos(a - b) = \cos(a) \cos(b) + \sin(a) \sin(b)$

$x = a - b$

$a = 60 \: \: \: b = 30$

$x = 60 - 30 = 30$

Answer 2

Solution:-

cos x = cos60° cos30° + sin60° sin30°

cos x = 1/2 × √3/2 + √(3)/2 × 1/2

cos x = √3/4 + √3/4

cos x = (√3 + √3)/4

cosx = 2√3/4

cosx = √3/2

cos x = 30°

x = 30°

Hence , cos(30°) = √3/2

value for x is 30°

More information:-

0 30° 60° 90°

cos 1 √3/2 1/2 0

sin 0 1/2 √3/2 1

tan 0 1/√3 √3 N.D

cosec N.D 2 2√3 1

sec 1 2√3 2 N.D

cot N.D √3 1/√3 N.D

Important formulas

sin²x + cos²x = 1

1 + tan²x = sec²x

1 + cot²x = cosec²x