Hi

The correct option is (c) ab <0 dear.

Explanation is provided below :-

cos2<0 as we know cos(pi/2)=0 and (pi/2)is somewhere around 1.57

so it lies in the second quadrant (where values lie for 1 to 4.71).

In second quadrant, cos value is negative .

sin7>0 as we know sin(pi/2)=1 and (pi)is somewhere around 6.28

so after one complete rotation it lies in the first quadrant (where values lie for 0 to 1.57) .

In first quadrant, sin value is positive.

so, ab<0  ,as a negative number multiplied by a positive number gives negative number .


Thankyou