Question

Basic trigonometry help needed.

Answer 1

Prove : \(\sin (90 - \theta) = \cos \theta\)

Answer 2

Actually I am confused that how can I : prove that sin in 2nd quadrant is +ve ? That is my basic confusion ...

Answer 3

can u use sin (A-B) formula?

Answer 4

No idea. Actually that was just in start and the formula arises later, so I think that there must be an easier method?

Answer 5

draw a right triangle

Answer 6

:( not so good but OK ? :)

Answer 7

nothing is there without naming , OK now I think.

Answer 8

now find sin 90-theta and cos theta using basic defination