Question

cos(cos^-1(-3/7)-tan^-1(-12/5))
Any help on finding the exact value of this expression would be greatly appreciated! Thanks!

Answer 1

well
first do you remember that
cos(a-b)=cos(a)cos(b)+sin(a)sin(b) ?

Answer 2

Ah, gotcha! I was just thinking about that!

Answer 3

let a=arccos(3/7) and b=arctan(-12/5)
so
cos(a)=3/7 and tan(b)=-12/5
draw two separate right triangles

Answer 4

let me know if you need anymore help

Answer 5

Got it, thanks!