Video Transcript
Simplify cos of two π times cos of
22π minus sin of two π times sin of 22π.
When we look at this expression, we
see that we have the angle two π and the angle 22π. We have the cos and sin of the
angle two π, and we have the cos and sin of the angle 22π, which means we have an
expression in the form cos of π΄ times cos of π΅ minus sin of π΄ times sin of
π΅. And we can simplify this expression
using the angle sum identities. We know that the cos of π΄ times
the cos of π΅ minus the sin of π΄ times the sin of π΅ is equal to the cos of π΄ plus
π΅. In our case, the angle π΄ is two π
and the angle π΅ is 22π, making this expression equal to cos of two π plus 22π,
cos of 24π. And so the simplified form of this
expression is cos of 24π.
