Question

if cos (40° +A) = sin 30° then A is​

Answer 1

Answer:

Cos(40+A)=sin 30

cos (40+A)=cos (90-30)

cos (40+A)=cos 60

40+A=60

A=60-40

A=20

value of A =20

If you manage to memorise the trigonometry ratio table then you can easily tackle such problems in second. Here we can directly consider which cos value of θ is equals to Sin 30. So, if you have remembered that sin 30 = cos 60. so, 40+A=60, A= 20. This will help you to save much time in exam hall.

Answer 2

Answer:

$your \: answer \: is \: 60 \:$

60°