[" (A) ",(ab)/(2(b-a))," (B) ",(ab)/(b-a)," (C) ",(3ab)/(2(b-a))," (D) ",(3ab)/((b-a))]

If log_(2)7= a and log_(3)2=b ," then the value of log_(14)84 is : (A) (1+3b+2ab)/(ab-b) (B) (1+2b+ab)/(b+ab) (C) (1+a+b)/(a+b) (D) (1+b+ab)/(a+ab)

If cos theta = (a cos phi + b) / (a + b cos phi) then (tan ((theta) / (2))) / (tan ((phi) / (2))) = (A) ( ab) / (a + b) (B) (a + b) / (ab) (C) sqrt ((a + b) / (ab)) (D) sqrt ((ab) / (a + b))

The lengths of the sides CB and CA of a triangle ABC are given by a and b and the angle C is (2pi)/(3) . The line CD bisects the angle C and meets AB at D . Then the length of CD is : (a) (1)/(a+b) (b) (a^(2)+b^(2))/(a+b) (c) (ab)/(2(a+b)) (d) (ab)/(a+b)

If the first second and last term of an A.P.are a,b, and 2a respectively then its sum is (ab)/(2(b-a)) b.(ab)/(b-a) c.(3ab)/(3(b-a)) d.none of these

tan [ i log ((a - ib)/(a + ib )) ] is equal to : a) ab b) (2 ab)/( a ^(2) - b ^(2)) c) (a ^(2) - b ^(2))/( 2 ab) d) (2 ab)/( a ^(2) + b ^(2))

If abs(a)=2, abs(b)=3" and "abs(2a-b)=5," then "abs(2a+b) equals

The factors of 8a^(3)+b^(3)-6ab+1 are (a) (2a+b-1)(4a^(2)+b^(2)+1-3ab-2a) (b) (2a-b+1)(4a^(2)+b^(2)-4ab+1-2a+b)(2a+b+1)(4a^(2)+b^(2)+1-2ab-b-2a) (d) (2a-1+b)(4a^(2)+1-4a-b-2ab)

Suppose a, b, c are three vectors such that abs(a)=abs(b)=abs(c)=1" and "a+b+c=0," then "abs(a-b)^(2)+abs(b-c)^(2)+abs(c-a)^(2)= _______