Practice problem
Given sin(a)=45\sin(a)=\frac45sin(a)=54 and cos(b)=13\cos(b)=\frac13cos(b)=31, with aaa and bbb both in the interval [0,π2)[0,\frac{\pi}2)[0,2π) find cos(a+b)\cos(a+b)cos(a+b).
−5−4615-\frac{\sqrt5-4\sqrt{6}}{15}−155−46
5−4615\frac{\sqrt5-4\sqrt{6}}{15}155−46
−3−8215-\frac{3-8\sqrt2}{15}−153−82
3−8215\frac{3-8\sqrt2}{15}153−82
Type a concept, like “slope” or “photosynthesis”.