[" 1.द्रशाइए कि दिक् -कोसाइन "(12)/(13),(-3)/(13),(-4)/(13);quad (4)/(13),(12)/(13),(3)/(13);quad (3)/(13),(-4)/(13),(12)/(13)" वाली तीन "],[" रवाएँ परस्पर लंववत् है। "]

(-4)/(13)+0=0+(-4)/(13)

Evaluate: (-3)/(13)+((-5)/(13))

(9)/(13)+(-8)/(13)+(4)/(3)+(-5)/(8)

Find: ((-8))/(13)+((-4))/(13)

((12)/(17)times(12)/(17)-(13)/(34)times(13)/(34))/((12)/(17)+(13)/(34))

(2/13)^(4/3)div(2/13)^(5/3)

Solve : 4/(13)+2/(13)+1/(13)

Solve : 4/(13)+2/(13)+1/(13)

Check if lines with direction-cosines : lt (12)/(13) , - (3)/(13) , - (4)/(13) gt , lt (4)/(13) , (12)/(13), (3)/(13) gt , lt (3)/(13) , (4)/(13) , (12)/(13) gt are mutually perpendicular .

Find : a. 4 (5)/(13)- 3 (7)/(13) + 2 (8)/(13)