Question

Prove that cos 0 (1 + tanº 0) = 1.​

Answer 1

We know that 1 + tan 0 = sec 0

therefore, cos 0 (1 + tan 0) = cos 0 (sec 0)

also, sec 0 = 1/cos 0

hence, cos 0 (1 + tan 0) = cos 0 × 1/cos 0

cos 0 in numerator and denominator get cancelled by simple division.

thus, cos 0 (1 + tan 0) = 1.