Which of the following is NOT a correct formula?
- Acos
2
Acot
2
A=cot
2
A−cos
2
A - Btan
2
A
1+tan
2
A
=sin
2
A - CsecAsinA=tanA
- Dcsc
2
A−cot
2
A=1
Solution & Step-by-step Explanation
Let's analyze option B:
LHS=
tan
2
A
1+tan
2
A
=
tan
2
A
sec
2
A
=
cos
2
A
sin
2
A
cos
2
A
1
=
sin
2
A
1
=csc
2
A
However, option B says it equals sin
2
A, which is incorrect. Therefore, B is NOT a correct formula.
LHS=
tan
2
A
1+tan
2
A
=
tan
2
A
sec
2
A
=
cos
2
A
sin
2
A
cos
2
A
1
=
sin
2
A
1
=csc
2
A
However, option B says it equals sin
2
A, which is incorrect. Therefore, B is NOT a correct formula.