Question

find the value of tan (a-b) if cos a=4/5 on the interval (270, 360) and sin b=-5/13 on the interval (270, 360)

Answer 1

We can find a and b using inverse trig functions,

`</p><p>\cos(a)=(4)/(5)\implies a=\arccos\Big((4)/(5)\Big)\approx36.87 \\</p><p>\sin(b)=-(5)/(13)\implies b=\arcsin\Big(-(5)/(13)\Big)\approx-22.62</p><p>`

`\tan(36.87-(-22.62))\approx1.7`

Hope this helps.