What is the value of cos((5pi)/7)cos((3pi)/5)-sin((5pi)/7)sin((3pi)/5) ?

The value of cos((5pi)/7)cos((3pi)/5)-sin((5pi)/7)sin((3pi)/5) is -0.55089…

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

Popular >

cos((5pi)/7)cos((3pi)/5)-sin((5pi)/7)sin((3pi)/5)

cos (\frac{5 π}{7}) cos (\frac{3 π}{5}) - sin (\frac{5 π}{7}) sin (\frac{3 π}{5})

- 0.55089 \dots

Solution steps

cos (\frac{5 π}{7}) cos (\frac{3 π}{5}) - sin (\frac{5 π}{7}) sin (\frac{3 π}{5})

Refine to a decimal form

= - 0.55089 \dots

cos (\frac{6 π}{6})

sin^{2} (7 0^{\circ}) + cos^{2} (7 0^{\circ})

arccos (tan (π))

tan (arctan (45))

cos (- 0.4)

What is the value of cos((5pi)/7)cos((3pi)/5)-sin((5pi)/7)sin((3pi)/5) ?
The value of cos((5pi)/7)cos((3pi)/5)-sin((5pi)/7)sin((3pi)/5) is -0.55089…