If ๐ is in Quadrant II and cos๐+sin๐=1/5, the value of ๐ ๐๐๐/๐ก๐๐๐ + ๐๐ ๐๐/๐๐๐ก๐ would be (A) 3/5 (B) -5/12 (C)5/12 (D) 1. Ans: B
One My typo.
Not
Not
[ 1 / ( cos ฮธ โ sin ฮธ / cos ฮธ ] + [ 1 / ( sin ฮธ โ cos ฮธ / sin ฮธ ] =
It should be like this
[ 1 / ( cos ฮธ โ sin ฮธ / cos ฮธ ) ] + [ 1 / ( sin ฮธ โ cos ฮธ / sin ฮธ ) ] =
To solve this problem, we need to use trigonometric identities and relationships.
First, let's recall the definitions of sine and cosine:
- In Quadrant II, both sine and cosine values are negative.
- The sine of an angle ๐ is equal to the ratio of the length of the opposite side to the length of the hypotenuse in a right triangle with angle ๐.
- The cosine of an angle ๐ is equal to the ratio of the length of the adjacent side to the length of the hypotenuse in a right triangle with angle ๐.
Given that ๐ is in Quadrant II, both sine and cosine are negative. Therefore, we can rewrite the given equation as:
cos๐ + (-sin๐) = 1/5
Now, let's simplify the expression we need to find:
๐ ๐๐๐/๐ก๐๐๐ + ๐๐ ๐๐/๐๐๐ก๐
Using the definitions and relationships of trigonometric functions, we can write the expression as:
(sin๐/cos๐) / (cos๐/sin๐) + (cos๐/sin๐) / (cos๐/sin๐)
Simplifying further:
(sin๐/cos๐) * (sin๐/cos๐) + (cos๐/sin๐) * (sin๐/cos๐)
(sin^2๐ + cos^2๐) / (cos๐ * sin๐)
Using the Pythagorean identity sin^2๐ + cos^2๐ = 1, we can simplify the expression to:
1 / (cos๐ * sin๐)
Now, let's substitute the given equation cos๐ + (-sin๐) = 1/5 to solve for cos๐ and sin๐:
cos๐ - sin๐ = 1/5
Rearranging the terms, we get:
cos๐ = 1/5 + sin๐
Squaring both sides of the equation, we get:
cos^2๐ = (1/5 + sin๐)^2
Expanding the equation:
cos^2๐ = 1/25 + 2/5 * sin๐ + sin^2๐
Using the Pythagorean identity sin^2๐ + cos^2๐ = 1, we can substitute sin^2๐ with 1 - cos^2๐:
cos^2๐ = 1/25 + 2/5 * sin๐ + (1 - cos^2๐)
Rearranging the terms, we get:
2 * cos^2๐ + 2/5 * sin๐ = 1/25 + 1
Simplifying the right side of the equation, we get:
2 * cos^2๐ + 2/5 * sin๐ = 26/25
Now, let's substitute the identity cos๐ + sin๐ = 1/5 into the equation:
2 * (1/5)^2 + 2/5 * sin๐ = 26/25
Simplifying, we get:
2/25 + 2/5 * sin๐ = 26/25
Multiplying through by 25, we get:
2 + 10 * sin๐ = 26
Rearranging the terms, we get:
10 * sin๐ = 24
Dividing both sides by 10, we get:
sin๐ = 24/10 = 12/5
Since we know that sine is negative in Quadrant II, we have:
sin๐ = -12/5
Now, let's substitute the values of sin๐ and cos๐ into the expression we simplified earlier:
๐ ๐๐๐/๐ก๐๐๐ + ๐๐ ๐๐/๐๐๐ก๐
((-12/5)/(1/5)) + ((1/5)/(-12/5))
Simplifying further, we get:
-12/1 + 1/(-12)
This can be rewritten as:
-12 - 1/12
Multiplying the integer part by the denominator of the fraction, we get:
(-12 * 12 - 1)/12
Simplifying the numerator, we get:
-144 - 1 = -145
Therefore, the final answer of the expression is -145/12, which is option (B) -5/12.
In summary, by using trigonometric identities, relationships, and the given equation, we found that the value of ๐ ๐๐๐/๐ก๐๐๐ + ๐๐ ๐๐/๐๐๐ก๐ is -5/12.
That is not calculus.
cos ฮธ + sin ฮธ = 1 / 5
Rise both sides to the power of two
( cos ฮธ + sin ฮธ )ยฒ = ( 1 / 5 )ยฒ
cosยฒ ฮธ + 2 sin ฮธ cos ฮธ + sinยฒ ฮธ = 1 / 25
2 sin ฮธ cos ฮธ + sinยฒ ฮธ + cosยฒ ฮธ = 1 / 25
2 sin ฮธ cos ฮธ + 1 = 1 / 25
Subtract 1 to both sides
2 sin ฮธ cos ฮธ = 1 / 25 - 1
2 sin ฮธ cos ฮธ = 1 / 25 - 25 / 25
2 sin ฮธ cos ฮธ = - 24 / 25
Multiply both sides by 1 / 2
sin ฮธ cos ฮธ = - 12 / 25
In Quadrant II sine is positive and cosine is negative so product of positive sine and negative cosine is negative.
This means:
sin ฮธ cos ฮธ = - 12 / 25 lie in Quadrant II
sec ฮธ / tan ฮธ + csc ฮธ / cot ฮธ = ( 1 / cos ฮธ ) / tan ฮธ + ( 1 / sin ฮธ ) / cot ฮธ =
[ 1 / ( cos ฮธ โ tan ฮธ ] + [ 1 / ( sin ฮธ โ cot ฮธ ] =
[ 1 / ( cos ฮธ โ sin ฮธ / cos ฮธ ] + [ 1 / ( sin ฮธ โ cos ฮธ / sin ฮธ ] =
1 / sin ฮธ + 1 / cos ฮธ = ( cos ฮธ + sin ฮธ ) / ( sin ฮธ cos ฮธ ) =
( 1 / 5 ) / ( - 12 / 25 ) = 1 โ 25 / 5 โ ( - 12 ) =
25 / 5 โ ( - 12 ) = 1 5cos ฮธ + sin ฮธ = 1 / 5
Rise both sides to the power of two
( cos ฮธ + sin ฮธ )ยฒ = ( 1 / 5 )ยฒ
cosยฒ ฮธ + 2 sin ฮธ cosฮธ + sinยฒ ฮธ = 1 / 25
2 sin ฮธ cosฮธ + sinยฒ ฮธ + cosยฒ ฮธ = 1 / 25
2 sin ฮธ cosฮธ + 1 = 1 / 25
Subtract 1 to both sides
2 sin ฮธ cosฮธ = 1 / 25 - 1
2 sin ฮธ cosฮธ = 1 / 25 - 25 / 25
2 sin ฮธ cosฮธ = - 24 / 25
Multiply both sides by 1 / 2
sin ฮธ cosฮธ = - 12 / 25
In Quadrant II sine is positive and cosine is negative so product of positive sine and negative cosine is negative.
This means:
sin ฮธ cosฮธ = - 12 / 25 lie in Quadrant II
sec ฮธ / tan ฮธ + csc ฮธ / cot ฮธ = ( 1 / cos ฮธ ) / tan ฮธ + ( 1 / sin ฮธ ) / cot ฮธ =
[ 1 / ( cos ฮธ โ tan ฮธ ] + [ 1 / ( sin ฮธ โ cot ฮธ ] =
[ 1 / ( cos ฮธ โ sin ฮธ / cos ฮธ ] + [ 1 / ( sin ฮธ โ cos ฮธ / sin ฮธ ] =
1 / sin ฮธ + 1 / cos ฮธ = ( cos ฮธ + sin ฮธ ) / ( sin ฮธ cos ฮธ ) =
( 1 / 5 ) / ( - 12 / 25 ) = 1 โ 25 / 5 โ ( - 12 ) = 5 โ 5 / 5 โ ( - 12 ) = - 5 / 12