2.0k views
1 vote
A right triangle has acute angles c and d . If c=15/17 and cos D=15/17 , what are cot d and c ?

User Rashy
by
8.5k points

1 Answer

3 votes

Final answer:

To find cot d in a right triangle with cos D = 15/17, we use the Pythagorean identity and find sin D = 8/17 and then cot D = 15/8. For angle c, assuming the original question meant to find cos c, we determine cos c = sin D, so cos c equals 8/17 as well.

Step-by-step explanation:

The question asks us to determine the values of cot d and angle c for a right triangle with acute angles c and d, given that the cosine of angle D (cos D) is 15/17. To find these values, we can use trigonometric identities and the fact that in a right triangle, the sum of the acute angles equals 90 degrees.

First, let's address the cosine of angle D. Given that cos D = 15/17, we can deduce that the adjacent side to angle D has a length of 15 and the hypotenuse has a length of 17 because the cosine of an angle in a right triangle is equal to the length of the adjacent side divided by the hypotenuse (cosine function of direction angle A, Ax/A = cos A).

To find the cotangent of angle D (cot d), which is the cosine of angle D divided by the sine of angle D, we need the sine of angle D. Due to the Pythagorean identity, sin2D + cos2D = 1. Since we already have cos D, we can solve for sin D. Using this, we find that sin D = sqrt(1 - cos2D) = sqrt(1 - (15/17)2) = sqrt(1 - 225/289) = sqrt(64/289) = 8/17. Now, cot D can be calculated as cot D = cos D / sin D = (15/17) / (8/17) = 15/8.

Regarding angle c, the question appears to be confusing as it equates the acute angle c with a ratio of 15/17. In trigonometry, an angle is usually represented by a letter and not a ratio. We should correct this to find the value of sin c or cos c. Assuming we're asked about cos c, since the sum of angles c and D is 90 degrees, and we already have cos D, we can deduce that cos c = sin D, because in a right triangle, the sine of one acute angle is equal to the cosine of the other acute angle. Therefore, cos c is also 8/17.

User Jodocus
by
8.0k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories