Q. If cot A = b/a, where a and b are real numbers, the value of sin2 A is equal to 
(A) b2 / a2 + b2                 (B)  a2 / a2 + b2 
(C) a /  √ a2 + b2                    (D) b/ √  a2  + b2 ​       
​    

given: ...........(1)

since ............(2)

therefore


cosec2A=1+b2a2=a2+b2a2So, sin2A=1cosec2A=a2a2+b2

hope this helps you.

cheers!!

  • -2
Cot A=adjacent/opposite 
adj=b , opp=a
hypotenuse=√(a² + b²)
Hypo²        =(√(a² + b²))²
                  = a² + b²
    
Sin²A = opp²/ hypo²
          = a²/ a² + b²
 
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