Question

Cos(60*-45*) exact value of expression

Answer 1

Explanation:

`\cos(60 \degree - 45 \degree) \\ =\cos \: 60 \degree \: \cos \: 45 \degree + \sin \: 60 \degree \: \sin \: 45 \degree \\ = (1)/(2) * (1)/( √(2) ) + ( √(3) )/(2) * (1)/( √(2)) \\ \\ = (1 + √(3) )/(2 √(2) ) \\ \\ </p><p></p><p>=(1 + 1.732)/(2 * 1.414 ) \\\\</p><p></p><p>=(2.732)/(2.828) \\\\</p><p>=0.966053748\\\\</p><p>\approx 0.966\\\\</p><p></p><p> \red { \boxed{\therefore \: cos(60 \degree - 45 \degree) \approx 0.966 }} \\`