determine-the-exact-values-of-cosxycosleftxyright-and-cosxycosleftx-yrightsinx31

Question

Determine the exact values of $\cos\left(x+y\right)$ and $\cos\left(x-y\right)$ .

$\sin x=\frac{3}{13}$ , $\sin y=-\frac27$ , $x$ in quadrant I and $y$ in quadrant III

Accepted Answer

$\cos\left(x+y\right)=\frac{6-60\sqrt2}{91}$ , $\cos\left(x-y\right)=\frac{-6-60\sqrt2}{91}$

Answer

$\cos\left(x+y\right)=\frac{6-60\sqrt2}{91}$ , $\cos\left(x-y\right)=\frac{6-60\sqrt2}{91}$

Answer

$\cos\left(x+y\right)=\frac{6-60\sqrt2}{91}$ , $\cos\left(x-y\right)=\frac{8\sqrt{10}-9\sqrt5}{91}$

Answer

$\cos\left(x+y\right)=\frac{6-60\sqrt2}{91}$ , $\cos\left(x-y\right)=\frac{-8\sqrt{10}-9\sqrt5}{91}$

Determine the exact values of cos(x+y)\cos\left(x+y\right)cos(x+y) and cos(x−y)\cos\left(x-y\right)cos(x−y).sinx=313\sin x=\frac{3}{13}sinx=133, siny=−27\sin y=-\frac27siny=−72, xxx in quadrant I and yyy in quadrant III