If is continuous at x = 0, find k.

Given:

f(x) is continuous at x = 0 & f(0) =

For f(x) to be continuous at x = 0,f(0)^{–} _{=} f(0) ^{+ =} f(0)

LHL = f(0)^{–} =

cos(–x) = cosx

f(0)^{–}

Since ,f(x) is continuous at x = 0 & f(0) =

k^{2} = 1

k =

27