What is the value of cos(65)cos(5)+sin(65)sin(5) ?

The value of cos(65)cos(5)+sin(65)sin(5) is 1/2

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cos(65)cos(5)+sin(65)sin(5)

cos (6 5^{\circ}) cos (5^{\circ}) + sin (6 5^{\circ}) sin (5^{\circ})

\frac{1}{2}

Solution steps

cos (6 5^{\circ}) cos (5^{\circ}) + sin (6 5^{\circ}) sin (5^{\circ})

Rewrite using trig identities:

cos (6 0^{\circ})

= cos (6 0^{\circ})

Use the following trivial identity:

cos (6 0^{\circ}) = \frac{1}{2}

= \frac{1}{2}

cos^{3} (18 0^{\circ})

\frac{8}{sin ( 3 5 ^{\circ} )}

sec (7 1^{\circ}) (3 0^{\circ})

9.8 cos (7 5^{\circ})

1 + cos (3 0^{\circ})

What is the value of cos(65)cos(5)+sin(65)sin(5) ?
The value of cos(65)cos(5)+sin(65)sin(5) is 1/2