Min. value of 13sinθ-4cosθ+7
512
112
712
16
Range of 3sinθ-4cosθ+7 is c-a2+b2,c+a2+b2=2,12
since 0∉2,12
⇒ Min. value of the function is =1max of 3sinθ-4cosθ+7
=17+25=112