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

Question

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)﻿.﻿sin⁡x=313\sin x=\frac{3}{13}sinx=133​﻿, ﻿sin⁡y=−27\sin y=-\frac27siny=−72​﻿, ﻿xxx﻿ in quadrant I and ﻿yyy﻿ in quadrant III

Accepted Answer

﻿cos⁡(x+y)=6−60291\cos\left(x+y\right)=\frac{6-60\sqrt2}{91}cos(x+y)=916−602​​﻿, ﻿cos⁡(x−y)=−6−60291\cos\left(x-y\right)=\frac{-6-60\sqrt2}{91}cos(x−y)=91−6−602​​﻿

Answer

﻿cos⁡(x+y)=−6−60291\cos\left(x+y\right)=\frac{-6-60\sqrt2}{91}cos(x+y)=91−6−602​​﻿, ﻿cos⁡(x−y)=6−60291\cos\left(x-y\right)=\frac{6-60\sqrt2}{91}cos(x−y)=916−602​​﻿

Answer

﻿cos⁡(x+y)=−810−9591\cos\left(x+y\right)=\frac{-8\sqrt{10}-9\sqrt5}{91}cos(x+y)=91−810​−95​​﻿, ﻿cos⁡(x−y)=810−9591\cos\left(x-y\right)=\frac{8\sqrt{10}-9\sqrt5}{91}cos(x−y)=91810​−95​​﻿

Answer

﻿cos⁡(x+y)=810−9591\cos\left(x+y\right)=\frac{8\sqrt{10}-9\sqrt5}{91}cos(x+y)=91810​−95​​﻿, ﻿cos⁡(x−y)=−810−9591\cos\left(x-y\right)=\frac{-8\sqrt{10}-9\sqrt5}{91}cos(x−y)=91−810​−95​​﻿

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=-\(\frac\)27siny=−72, xxx in quadrant I and yyy in quadrant III

Determine the exact values of $\(\cos\]\left\)(x+y\(\right\))$ and $\(\cos\]\left\)(x-y\(\right\))$ .
$\sin\) x=\(\frac{3}{13}$ , $\(\sin\) y=-\(\frac\)27$ , $x$ in quadrant I and $y$ in quadrant III