Question

if secA-tanA = a,
then the value of sinA =​

Answer 1

Answers : (1)

we know that sec^2 A - tan^2 A =1 and it is given that

sec A -tan A =a

dividing equation 1 with 2, we get

sec A + tan A = 1/a

also sec A - tan A = a

adding and subtracting these equations, we get

sec A = (a + 1/a )/2

& tan A = (1/a -a)/2

thus, sin A = (sin A/ cos A) / (1/cos A) = tan A / sec A =( 1-a^2) / (1+ a^2)