If `r/(r_1)=(r_2)/(r_3),` then `A=90^0` (b) `B=90^0` `C=90^0` (d) none of these

If r/(r_1)=(r_2)/(r_3), then (a) A=90^0 (b) B=90^0 (c) C=90^0 (d) none of these

If (r)/(r_(1))=(r_(2))/(r_(3)) ,then A=90^(@)(b)B=90^(@)C=90^(@) (d) none of these

If an a triangle A B C ,(2cosA)/a+(cosB)/b+(2cosC)/c=a/(b c)+b/(a c), find the /_A= 90^0 (b) 60^0 (c) 30^0 (d) none of these

If (r)/(r _(1))= (r_(2))/(r _(3)), then show that c=90^(@).

If an a triangle A B C ,(2cosA)/a+(cosB)/b+(2cosC)/c=a/(b c)+b/(a c), find the /_A= (a) 90^0 (b) 60^0 (c) 30^0 (d) none of these

If A B , B C a n d C D are equal chords of a circle with O as centre and A D diameter, then /_A O B= 60^0 (b) 90^0 (c) 120^0 (d) none of these

If A B ,\ B C\ a n d\ C D are equal chords of a circle with O as centre and A D diameter, then /_A O B= (a) 60^0 (b) 90^0 (c) 120^0 (d) none of these

If (1+x)^n=sum_(r=0)^n a_r x^r and b_r=1+(a_r)/(a_(r-1)) and prod_(r=1)^n b_r=((101)^(100))/(100!), then n equals to: 99 (b) 100 (c) 101 (d) None of these

If sum_(r=1)^n t_r= (n(n+1)(n+2))/3 then sum _(r=1)^oo 1/t_r= (A) -1 (B) 1 (C) 0 (D) none of these