मराठी
महाराष्ट्र राज्य शिक्षण मंडळएचएससी विज्ञान (सामान्य) इयत्ता ११ वी

If log(x-y4)=logx+logy, show that (x + y)2 = 20xy - Mathematics and Statistics

Advertisements
Advertisements

प्रश्न

If `log(( x - y)/4) = logsqrt(x) + log sqrt(y)`, show that (x + y)2 = 20xy 

बेरीज

उत्तर

`log(( x - y)/4) = logsqrt(x) + log sqrt(y)`

∴ `log((x - y)/4) = log(sqrt(x) sqrt(y))`  ...[log m + log n = log mn]

∴ `log((x - y)/4) = logsqrt(xy)`

∴ `(x - y)/4 = sqrt(xy)`

Squaring on both sides, we get

`(x - y)^2/16` = xy

∴ x2 – 2xy + y2 = 16xy

Adding 4xy on both sides, we get

x2 + 2xy + y2 = 20xy

∴ (x + y)2 = 20xy

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 6: Functions - Exercise 6.1 [पृष्ठ ११९]

संबंधित प्रश्‍न

Let f : R+ → R, where R+ is the set of all positive real numbers, such that f(x) = loge x. Determine

(b) {x : f(x) = −2}


Let X = {1, 2, 3, 4} and Y = {1, 5, 9, 11, 15, 16}
Determine which of the set are functions from X to Y.

(b) f2 = {(1, 1), (2, 7), (3, 5)}


et A = (12, 13, 14, 15, 16, 17) and f : A → Z be a function given by
f(x) = highest prime factor of x.
Find range of f.


If  \[f\left( x \right) = \frac{x + 1}{x - 1}\] , show that f[f[(x)]] = x.

 

 


If f(x) = loge (1 − x) and g(x) = [x], then determine function:

(i) f + g

 


If fg and h are real functions defined by 

\[f\left( x \right) = \sqrt{x + 1}, g\left( x \right) = \frac{1}{x}\] and h(x) = 2x2 − 3, find the values of (2f + g − h) (1) and (2f + g − h) (0).
 
 

If\[f\left( x \right) = 1 - \frac{1}{x}\] , then write the value of \[f\left( f\left( \frac{1}{x} \right) \right)\]

 

 


Let A = {1, 2, 3} and B = {2, 3, 4}. Then which of the following is a function from A to B? 

 


If f(x) = cos (log x), then the value of f(xf(y) −\[\frac{1}{2}\left\{ f\left( \frac{x}{y} \right) + f\left( xy \right) \right\}\] is

 

The range of f(x) = cos [x], for π/2 < x < π/2 is


If \[f\left( x \right) = \log \left( \frac{1 + x}{1 - x} \right)\] , then \[f\left( \frac{2x}{1 + x^2} \right)\]  is equal to

 

 


Which of the following relations are functions? If it is a function determine its domain and range:

{(1, 1), (3, 1), (5, 2)}


If f(x) =` (2x−1)/ (5x−2) , x ≠ 2/5` Verify whether (fof) (x) = x


Find the domain and range of the following function.

f(x) = `root(3)(x + 1)`


Find the domain and range of the following function.

f(x) = `sqrt((x - 3)/(7 - x))`


Express the following exponential equation in logarithmic form

54° = 1


Express the following logarithmic equation in exponential form

log2 64 = 6


Prove that alogcb = blogca


Solve for x.

x + log10 (1 + 2x) = x log10 5 + log10 6


If x = loga bc, y = logb ca, z = logc ab then prove that `1/(1 + x) + 1/(1 + y) + 1/(1 + z)` = 1


Select the correct answer from given alternatives.

If log (5x – 9) – log (x + 3) = log 2 then x = ...............


Answer the following:

Find whether the following function is one-one

f : R − {3} → R defined by f(x) = `(5x + 7)/(x - 3)` for x ∈ R − {3}


Answer the following:

If b2 = ac. prove that, log a + log c = 2 log b


Answer the following:
If log3 [log2 (log3x)] = 1, show that x = 6561

Answer the following:

Find value of `(3 + log_10 343)/(2 + 1/2 log_10 (49/4) + 1/2 log_10 (1/25)`


Answer the following:

If `log_2"a"/4 = log_2"b"/6 = log_2"c"/(3"k")` and a3b2c = 1 find the value of k


Answer the following:

Find the domain of the following function.

f(x) = `(x^2 + 4x + 4)/(x^2 + x - 6)`


Answer the following:

Find the range of the following function.

f(x) = `x/(9 + x^2)`


Answer the following:

Find the range of the following function.

f(x) = [x] – x


A graph representing the function f(x) is given in it is clear that f(9) = 2

Describe the following Range


The data in the adjacent table depicts the length of a person's forehand and their corresponding height. Based on this data, a student finds a relationship between the height (y) and the forehand length (x) as y = ax + b, where a, b are constant.

Length ‘x’ of
forehand (in cm)
Height 'y' 
(in inches)
35 56
45 65
50 69.5
55 74

Check if this relation is a function


The data in the adjacent table depicts the length of a person's forehand and their corresponding height. Based on this data, a student finds a relationship between the height (y) and the forehand length (x) as y = ax + b, where a, b are constant.

Length ‘x’ of
forehand (in cm)
Height 'y' 
(in inches)
35 56
45 65
50 69.5
55 74

Find a and b


Find the range of the following functions given by `|x - 4|/(x - 4)`


Find the range of the following functions given by f(x) = 1 + 3 cos2x

(Hint: –1 ≤ cos 2x ≤ 1 ⇒ –3 ≤ 3 cos 2x ≤ 3 ⇒ –2 ≤ 1 + 3cos 2x ≤ 4)


Let f(x) = `sqrt(1 + x^2)`, then ______.


If f(x) = `log_e{((1 - x))/((1 - x))}, |x| < 1, f{(2x)/((1 + x^2))}` is equal to ______.


The period of the function

f(x) = `(sin 8x cos x - sin 6x cos 3x)/(cos 2x cos x - sin 3x sin 4x)` is ______.


The domain of f(x) = `sin^-1 [log_2(x/2)]` is ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×