Evaluate: (i) (ii) (iii) Cos 48° – sin 42° (iv) Cosec 31° – sec 59°

Question

Evaluate: (i) (ii) (iii) Cos 48&#xB0; &#x2013; sin 42&#xB0; (iv) Cosec 31&#xB0; &#x2013; sec 59&#xB0;

Philoid · Accepted Answer

(i)

= 1

(ii)

(iii) cos 48^o - sin 42^o

= cos (90^o - 42^o) – sin 42^o

= sin 42^o - sin 42^o

= 0

(iv) cosec 31^o - sec 59^o

= cosec(90^o - 59^o) – sec 59^o

= sec 59^o - sec 59^o

= 0