Answer:
- cos 25°
Step-by-step explanation:
Cosine function is one of the trigonometric functions. Cosine function is regarded as an even function, which means that f(-x) = f(x). Also, cosine function is positive in the first quadrant and the last quadrant and negative in the second quadrant and the third quadrant. 155° lies in the second quadrant since 155° is smaller than 180°. Therefore, the basic angle or the reference angle of 155° is 180° - 155° = 25°. We know that cos 155° will be negative because it lies in the second quadrant and cos 25° will be positive because it lies in the first quadrant. Since cos 55° is positive, and cos (-25°) = cos 25° by the even function property, therefore option 2 and option 3 are incorrect since cos 155° is negative. Therefore, option 1 is the correct answer i.e. cos 155° = - cos 25°!!!
Answer:
the time taken for the ball to hit the ground is 9.4s
Answer: 9
If you multiply 8*9 you get 72
Answer:
Step-by-step explanation:
Given the vectors based on the number line as RS = 7y +3, ST = 5y +8, and RT = 83, the equation RS+ST = RT will be used to get the unknown.
Substituting the given equation into the expression we will have;
7y +3+5y +8 = 83
collect like terms'
7y+5y+3+8 = 83
12y + 11 = 83
12y = 83-11
12y = 72
y = 72/12
y = 6
b) Substitute y = 6 into RS and ST
Given RS = 7y+3
RS = 7(6)+3
RS = 42+3
RS = 45
For ST;
ST = 5y+8
ST = 5(6)+8
ST = 30+8
ST = 38