Question

The value of pi/2 is a solution for the equation 2sin^2x-sinx-1=0 . is it true or false

False rightt ???

Answer 1

\(\large\color{blue}{ \rm 2a^{2}-a-1=0 }\)
\(\large\color{blue}{ \rm (2a+1)(a-1)=0 }\)

\(\large\color{blue}{ \rm a=~-\frac{1}{2} ~~~or ~~~ 1~~ }\)

Is \(\large\color{blue}{ \rm sin^{-1}1 }\) or \(\large\color{blue}{ \rm sin^{-1}~(-\frac{1}{2}) }\) equal to π/2 ?

Answer 2

Yes

Answer 3

False.

Answer 4

hey, sin (pi/2) =1, so that sin^2 (pi/2) = 1^2 =1
replace to the expression
2*1 -1-1 =0
0 =0
it 's always true -->. pi/2 is one of the solutions.