Solve following algebraic equation
\[\sqrt {4 + 2{\text{x - }}{{\text{x}}^2}} = {\text{x}} - 2\]
Answer
680.4k+ views
Hint: Proceed the solution of this question, first by squaring on both then we can find the value of x either considering it as a quadratic equation or using Zero Product Property, we can also find the desired values of x.
Complete step-by-step answer:
In this question it is given a algebraic equation\[\sqrt {4 + 2{\text{x - }}{{\text{x}}^2}} = {\text{x}} - 2\]
Hence to solve, square on both side
\[{\left( {\sqrt {4 + 2{\text{x - }}{{\text{x}}^2}} } \right)^2} = {\left( {{\text{x}} - 2} \right)^2}\]
[ Using identity ${\left( {{\text{a - b}}} \right)^2} = \left( {{{\text{a}}^2} + {{\text{b}}^2} - 2{\text{ab}}} \right)$] where a = x and b = 2
\[ \Rightarrow 4 + 2{\text{x - }}{{\text{x}}^2} = {{\text{x}}^2} - 4{\text{x + 4 }}\]
On bringing terms on same side
\[ \Rightarrow 2{{\text{x}}^2} - 6{\text{x + 0 = 0 }}\]
Above expression we can considered as a quadratic equation \[2{{\text{x}}^2} - 6{\text{x + 0 = 0 }}\]
Sridharacharya formula is actually the quadratic formula, used for finding the roots of a quadratic equation \[{\text{a}}{{\text{x}}^2}{\text{ + bx + c = 0}}\] , where a not equal to 0 , & a, b, c are real coefficients of the equation \[{\text{a}}{{\text{x}}^2}{\text{ + bx + c = 0}}\]
Being quadratic it has 2 roots.
X = $\dfrac{{\left( { - {\text{b + }}\sqrt {{{\text{b}}^2} - 4{\text{ac}}} } \right)}}{{2{\text{a}}}}{\text{ & }}\dfrac{{\left( { - {\text{b - }}\sqrt {{{\text{b}}^2} - 4{\text{ac}}} } \right)}}{{2{\text{a}}}}$...... (1)
On comparing the given equation \[2{{\text{x}}^2} - 6{\text{x + 0 = 0 }}\] with the general quadratic equation \[{\text{a}}{{\text{x}}^2}{\text{ + bx + c = 0}}\] we got values of coefficients a = 2, b = -6, c = 0
On putting the value of coefficients a, b, c in equation (1)
${\text{x = }}\dfrac{{\left( { - ( - 6){\text{ + }}\sqrt {{{( - 6)}^2} - 4 \times (2) \times (0)} } \right)}}{{2 \times 2}}{\text{ & }}\dfrac{{\left( { - ( - 6){\text{ - }}\sqrt {{{( - 6)}^2} - 4 \times (2) \times (0)} } \right)}}{{2 \times 2}}$
${\text{x = }}\dfrac{{\left( {{\text{6 + 6}}} \right)}}{4}{\text{ = 3 & }}\dfrac{{\left( {{\text{6 - 6}}} \right)}}{4} = 0$
We know that if discriminant D $ \geqslant {\text{0}}$ then it will give real and distinct roots.
Here D ${\text{ = }}\sqrt {{{( - 6)}^2} - 4 \times 2 \times (0)} {\text{ = 6 }} \geqslant {\text{0}}$ Therefore we got two distinct real roots ${{\text{x}}_1}{\text{ = 3 & }}{{\text{x}}_2}{\text{ = 0}}$
Hence there will be two values of x i.e. 3 and 0 which will satisfy the above equation.
Note- this type of particular question we can also solve by using quadratic equations because the constant term was zero over there. So after this step we can also solve like
\[ \Rightarrow 2{{\text{x}}^2} - 6{\text{x + 0 = 0 }}\]
Taking 2x as a common
\[ \Rightarrow 2{\text{x}}{\text{.(x - 3) = 0 }}\]
Hence with the help of the "Zero Product Property" says that:
If a × b = 0 then either a = 0 or b = 0 (or both a=0 and b=0)
Hence in the above case, we can directly say either 2x=0 or (x-3) =0
$\because $ 2x=0 ⇒ x=0
$\because $ (x-3) =0 ⇒ x=3
Complete step-by-step answer:
In this question it is given a algebraic equation\[\sqrt {4 + 2{\text{x - }}{{\text{x}}^2}} = {\text{x}} - 2\]
Hence to solve, square on both side
\[{\left( {\sqrt {4 + 2{\text{x - }}{{\text{x}}^2}} } \right)^2} = {\left( {{\text{x}} - 2} \right)^2}\]
[ Using identity ${\left( {{\text{a - b}}} \right)^2} = \left( {{{\text{a}}^2} + {{\text{b}}^2} - 2{\text{ab}}} \right)$] where a = x and b = 2
\[ \Rightarrow 4 + 2{\text{x - }}{{\text{x}}^2} = {{\text{x}}^2} - 4{\text{x + 4 }}\]
On bringing terms on same side
\[ \Rightarrow 2{{\text{x}}^2} - 6{\text{x + 0 = 0 }}\]
Above expression we can considered as a quadratic equation \[2{{\text{x}}^2} - 6{\text{x + 0 = 0 }}\]
Sridharacharya formula is actually the quadratic formula, used for finding the roots of a quadratic equation \[{\text{a}}{{\text{x}}^2}{\text{ + bx + c = 0}}\] , where a not equal to 0 , & a, b, c are real coefficients of the equation \[{\text{a}}{{\text{x}}^2}{\text{ + bx + c = 0}}\]
Being quadratic it has 2 roots.
X = $\dfrac{{\left( { - {\text{b + }}\sqrt {{{\text{b}}^2} - 4{\text{ac}}} } \right)}}{{2{\text{a}}}}{\text{ & }}\dfrac{{\left( { - {\text{b - }}\sqrt {{{\text{b}}^2} - 4{\text{ac}}} } \right)}}{{2{\text{a}}}}$...... (1)
On comparing the given equation \[2{{\text{x}}^2} - 6{\text{x + 0 = 0 }}\] with the general quadratic equation \[{\text{a}}{{\text{x}}^2}{\text{ + bx + c = 0}}\] we got values of coefficients a = 2, b = -6, c = 0
On putting the value of coefficients a, b, c in equation (1)
${\text{x = }}\dfrac{{\left( { - ( - 6){\text{ + }}\sqrt {{{( - 6)}^2} - 4 \times (2) \times (0)} } \right)}}{{2 \times 2}}{\text{ & }}\dfrac{{\left( { - ( - 6){\text{ - }}\sqrt {{{( - 6)}^2} - 4 \times (2) \times (0)} } \right)}}{{2 \times 2}}$
${\text{x = }}\dfrac{{\left( {{\text{6 + 6}}} \right)}}{4}{\text{ = 3 & }}\dfrac{{\left( {{\text{6 - 6}}} \right)}}{4} = 0$
We know that if discriminant D $ \geqslant {\text{0}}$ then it will give real and distinct roots.
Here D ${\text{ = }}\sqrt {{{( - 6)}^2} - 4 \times 2 \times (0)} {\text{ = 6 }} \geqslant {\text{0}}$ Therefore we got two distinct real roots ${{\text{x}}_1}{\text{ = 3 & }}{{\text{x}}_2}{\text{ = 0}}$
Hence there will be two values of x i.e. 3 and 0 which will satisfy the above equation.
Note- this type of particular question we can also solve by using quadratic equations because the constant term was zero over there. So after this step we can also solve like
\[ \Rightarrow 2{{\text{x}}^2} - 6{\text{x + 0 = 0 }}\]
Taking 2x as a common
\[ \Rightarrow 2{\text{x}}{\text{.(x - 3) = 0 }}\]
Hence with the help of the "Zero Product Property" says that:
If a × b = 0 then either a = 0 or b = 0 (or both a=0 and b=0)
Hence in the above case, we can directly say either 2x=0 or (x-3) =0
$\because $ 2x=0 ⇒ x=0
$\because $ (x-3) =0 ⇒ x=3
Recently Updated Pages
If x a + bt + ct2 where x is in meters and t is in class 11 physics CBSE

A car covers the first half distance between two places class 11 physics CBSE

The resultant of two vectors overrightarrow P and overrightarrow class 11 physics CBSE

Find the value of cos 135 class 11 maths CBSE

A mass M is held in place by an applied force F and class 11 physics CBSE

A solution of glucose in water is labelled as 10 dfracwv class 11 chemistry CBSE

Trending doubts
Find the value of the expression given below sin 30circ class 11 maths CBSE

One Metric ton is equal to kg A 10000 B 1000 C 100 class 11 physics CBSE

Draw a diagram of nephron and explain its structur class 11 biology CBSE

10 examples of friction in our daily life

Proton was discovered by A Thomson B Rutherford C Chadwick class 11 chemistry CBSE

Bond order ofO2 O2+ O2 and O22 is in order A O2 langle class 11 chemistry CBSE

