How do you solve $\sin x = \dfrac{{\sqrt 2 }}{2}$
Answer
630k+ views
Hint: Here we will simplify the given equation and then by using the trigonometric table for doing some simplification, we will find the value of $x$.
Complete step-by-step solution:
The given term is: $\sin x = \dfrac{{\sqrt 2 }}{2}$
Now we know that $2 = \sqrt 2 \times \sqrt 2 $, therefore on substituting it with the denominator of the right-hand side we get:
$ \Rightarrow \sin x = \dfrac{{\sqrt 2 }}{{\sqrt 2 \times \sqrt 2 }}$
Now on simplifying we get:
$ \Rightarrow \sin x = \dfrac{1}{{\sqrt 2 }}$
Now from the trigonometric table we know that:
$ \Rightarrow \sin \left( {\dfrac{\pi }{4}} \right) = \left( {\sin \pi - \left( {\dfrac{\pi }{4}} \right)} \right)$
This can be written as:
$ \Rightarrow \sin \left( {\dfrac{{3\pi }}{4}} \right)$
This has the value:
$ \Rightarrow \dfrac{1}{{\sqrt 2 }}$ therefore,
$x = {\left( {\dfrac{\pi }{4}} \right)^c}$ which is ${45^\circ }$, $x = {\left( {\dfrac{{3\pi }}{4}} \right)^c}$ which is ${135^\circ }$
Therefore, on generalizing the answer we get:
$x = \left( {2n\pi + \dfrac{\pi }{4}} \right)or\left( {2n\pi + \dfrac{{3\pi }}{4}} \right),n \to \varepsilon \to \mathbb{Z}$, which is the required answer.
Therefore the value of x from $\sin x = \dfrac{{\sqrt 2 }}{2}$ is equal to $45^\circ$.
Note: This question can also be done by using the inverse trigonometric function as:
We have the given equation after simplification as:
$ \Rightarrow \sin x = \dfrac{1}{{\sqrt 2 }}$
Now using the inverse trigonometric function, we get:
$ \Rightarrow x = {\sin ^{ - 1}}\left( {\dfrac{1}{{\sqrt 2 }}} \right)$
Therefore, the principal value of $\sin x$ is $\dfrac{\pi }{4}$
Now since sine is positive in the first and second quadrant, we will subtract the principal value from $\pi $to get the solution in the second quadrant.
Therefore,
$ \Rightarrow \pi - \dfrac{\pi }{4}$
On simplifying we get:
$ \Rightarrow \dfrac{{3\pi }}{4}$, which is the solution in the second quadrant.
Therefore, on generalizing the answer we get:
$ \Rightarrow x = \left( {2n\pi + \dfrac{\pi }{4}} \right)or\left( {2n\pi + \dfrac{{3\pi }}{4}} \right),n \to \varepsilon \to \mathbb{Z}$, which is the required answer.
It is to be remembered which trigonometric functions are positive and negative in what quadrants.
The formula used over here is for $\sin (n\pi + x)$ ,
It is to be remembered that $\sin (n\pi + x) = {( - 1)^n}\sin x$
Basic trigonometric formulas should be remembered to solve these types of sums.
The inverse trigonometric function of $\sin x$ which is ${\sin ^{ - 1}}x$ used in this sum
For example, if $\sin x = a$ then $x = {\sin ^{ - 1}}a$
And ${\sin ^{ - 1}}(\sin x) = x$ is a property of the inverse function.
There also exists inverse function for the other trigonometric relations such as tan and cos.
The inverse function is used to find the angle $x$ from the value of the trigonometric relation.
Complete step-by-step solution:
The given term is: $\sin x = \dfrac{{\sqrt 2 }}{2}$
Now we know that $2 = \sqrt 2 \times \sqrt 2 $, therefore on substituting it with the denominator of the right-hand side we get:
$ \Rightarrow \sin x = \dfrac{{\sqrt 2 }}{{\sqrt 2 \times \sqrt 2 }}$
Now on simplifying we get:
$ \Rightarrow \sin x = \dfrac{1}{{\sqrt 2 }}$
Now from the trigonometric table we know that:
$ \Rightarrow \sin \left( {\dfrac{\pi }{4}} \right) = \left( {\sin \pi - \left( {\dfrac{\pi }{4}} \right)} \right)$
This can be written as:
$ \Rightarrow \sin \left( {\dfrac{{3\pi }}{4}} \right)$
This has the value:
$ \Rightarrow \dfrac{1}{{\sqrt 2 }}$ therefore,
$x = {\left( {\dfrac{\pi }{4}} \right)^c}$ which is ${45^\circ }$, $x = {\left( {\dfrac{{3\pi }}{4}} \right)^c}$ which is ${135^\circ }$
Therefore, on generalizing the answer we get:
$x = \left( {2n\pi + \dfrac{\pi }{4}} \right)or\left( {2n\pi + \dfrac{{3\pi }}{4}} \right),n \to \varepsilon \to \mathbb{Z}$, which is the required answer.
Therefore the value of x from $\sin x = \dfrac{{\sqrt 2 }}{2}$ is equal to $45^\circ$.
Note: This question can also be done by using the inverse trigonometric function as:
We have the given equation after simplification as:
$ \Rightarrow \sin x = \dfrac{1}{{\sqrt 2 }}$
Now using the inverse trigonometric function, we get:
$ \Rightarrow x = {\sin ^{ - 1}}\left( {\dfrac{1}{{\sqrt 2 }}} \right)$
Therefore, the principal value of $\sin x$ is $\dfrac{\pi }{4}$
Now since sine is positive in the first and second quadrant, we will subtract the principal value from $\pi $to get the solution in the second quadrant.
Therefore,
$ \Rightarrow \pi - \dfrac{\pi }{4}$
On simplifying we get:
$ \Rightarrow \dfrac{{3\pi }}{4}$, which is the solution in the second quadrant.
Therefore, on generalizing the answer we get:
$ \Rightarrow x = \left( {2n\pi + \dfrac{\pi }{4}} \right)or\left( {2n\pi + \dfrac{{3\pi }}{4}} \right),n \to \varepsilon \to \mathbb{Z}$, which is the required answer.
It is to be remembered which trigonometric functions are positive and negative in what quadrants.
The formula used over here is for $\sin (n\pi + x)$ ,
It is to be remembered that $\sin (n\pi + x) = {( - 1)^n}\sin x$
Basic trigonometric formulas should be remembered to solve these types of sums.
The inverse trigonometric function of $\sin x$ which is ${\sin ^{ - 1}}x$ used in this sum
For example, if $\sin x = a$ then $x = {\sin ^{ - 1}}a$
And ${\sin ^{ - 1}}(\sin x) = x$ is a property of the inverse function.
There also exists inverse function for the other trigonometric relations such as tan and cos.
The inverse function is used to find the angle $x$ from the value of the trigonometric relation.
Recently Updated Pages
Which of the following graphs shows the variation of class 12 physics CBSE

Draw a labelled diagram of the human male reproductive class 12 biology CBSE

Describe the experiment to compare the emf of two cells class 12 physics CBSE

What is standard hydrogen electrode

What is conventional current and electric current class 12 physics CBSE

2Bromopentane is treated with an alcoholic KOH solution class 12 chemistry CBSE

Trending doubts
Draw a labelled sketch of the human eye class 12 physics CBSE

Which are the Top 10 Largest Countries of the World?

A member of Simon commission later became Prime Minister class 12 social science CBSE

Draw ray diagrams each showing i myopic eye and ii class 12 physics CBSE

Give one example of a reptile that is viviparous class 12 biology CBSE

Which is the correct genotypic ratio of mendel dihybrid class 12 biology CBSE

