What is the value of cos(15)cos(75)-sin(15)sin(75) ?

The value of cos(15)cos(75)-sin(15)sin(75) is 0

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cos(15)cos(75)-sin(15)sin(75)

cos (1 5^{\circ}) cos (7 5^{\circ}) - sin (1 5^{\circ}) sin (7 5^{\circ})

0

Solution steps

cos (1 5^{\circ}) cos (7 5^{\circ}) - sin (1 5^{\circ}) sin (7 5^{\circ})

Rewrite using trig identities:

cos (9 0^{\circ})

= cos (9 0^{\circ})

Use the following trivial identity:

cos (9 0^{\circ}) = 0

= 0

50 \cdot sin (3 0^{\circ})

\frac{1}{2} sin (2 π)

- sin (- \frac{π}{4})

arctan (2 π)

arctan (\frac{- 2}{- 2})

What is the value of cos(15)cos(75)-sin(15)sin(75) ?
The value of cos(15)cos(75)-sin(15)sin(75) is 0