Question

If a+b= pi/2, prove that the maximum value of cosacosb 1/2

Answer 1

cosacosb=(1/2)*(cos(a+b)+cos(a-b))
since a+b is 90 degrees cos(a+b) is 0
so cosacosb=1/2*cos(a-b)
max value of cos function is 1 when a=b=45 degrees I.e a-b=0
hence max value is 1/2

Answer 2

here ur answer
hope it help u