Value of cos65°cos12°+sin65° sin12° -The Answer must be in either sin or cos and must be followed with a degree (i.e. cos88°) 1.6
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Originally Posted by ceroseven Value of cos65°cos12°+sin65° sin12° -The Answer must be in either sin or cos and must be followed with a degree (i.e. cos88°) 1.6 You want the seccend sum or difference identity, here Table of Trigonometric Identities
How would this be substituted in the equation?
Originally Posted by ceroseven How would this be substituted in the equation? Let $\displaystyle u=65^\circ$ and let $\displaystyle v=12^\circ$, then your problem reduces to $\displaystyle \cos65^\circ\cos12^\circ+\sin65^\circ\sin12^\circ= \cos(65^\circ-12^\circ)=\cos53^\circ$
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