Question

prove that sin(90-Q)=cosQ​

Answer 1

Answer:

triangles have 3 angles that add to 180 degrees. Therefore, if one angle is 90 degrees we can figure out Sin Theta = Cos (90 - Theta) and Cos Theta = Sin (90 - Theta).

Step-by-step explanation:

is the correct answer and mark as brainly answer

Answer 2

Answer:

Step-by-step explanation:

To Prove :-

sin(90° - Q) = cosQ

How To Prove :-

As they given that L.H.S is 'sin(90° - Q)' we can see that it is form of sin(A - B) so we need to expand it by using the formula of 'sin(A - B)' and we need to substitute the value of sin90° and cos90° and we need to prove that.

Formula Required :-

1) sin(A - B) = sinAcosB - cosAsinB

2) sin90° = 1

3) cos90° = 0

Solution :-

Taking L.H.S :-

= sin(90 - Q)

= sin90cosQ - cos90sinQ

[ ∴ sin(A - B) = sinAcosB - cosAsinB ]

=( 1 × cosQ) - (0 × sinQ)

[ ∴ sin90° = 1 , cos90° = 0 ]

= cosQ - 0

= cosQ

= R.H.S

Hence Proved.