Question

If cos a+cosb=2,then find the valur of cos^2a/2+cos^2b/2

Answer 1

Step-by-step explanation:

we know that

cos a=2cos^2(a/2) -1

so. cos^2(a/2)= ( cos a +1)/2

similarly

cos^2(b/2)=(cos b +1)/2

put the value—

= (cos a +1)/2 +(cos b+1)/2

= (cos a + cos b +2)/2

= ( 2+2)/2

= 2