Answer:
Yes, they are equal in the values (in radians):
π/4, 5π/4
If cos(x) and sin(x) are defined to you as nonnegative functions (in terms of lengths), then 3π/4 and 7π/4 are also included
Step-by-step explanation:
Remember that odd multiples of 45° are special angles, with the same sine and cosine values (you can prove this, for example, by considering a right triangle with an angle of 45° and hypotenuse with length 1, and finding the trigonometric ratios).
The radian measure of 45° corresponds to π/4, hence the odd multiples on the interval [0, 2π) are π/4, 3π/4, 5π/4, 7π/4.
If you define sin(x) and cos(x) using the cartesian coordinate system (via unit circle), then cos(3π/4)=-sin(3π/4) and cos(7π/4)=-sin(7π/4). In this case, only π/4 and 5π/4 are valid choices.
Take the sequence in 1a
The 10th term is 31
The 20th is 61
If you wanted to find these by continuing the series, you'd have to add 3 to the last number in the series, then 3 more, then 3 more, until you reach the 20th term. By this point, you will have added 3 to the first term 19 times. That's where the formula comes from. So here,
a = 4, the first term
n = 20, the number of the term we need
d = 3, how much we're adding each time between one term and the next
Then, to get the 20th term,
4 + (20 - 1) • 3 = 4 + (19 • 3) = 4 + 57 = 61
Answers
The 10th and 20th terms of each sequences are
a. 31; 61
b. 48; 98
c. 47; 97
(in <em>c</em>, you're adding the same <em>d</em> as in the sequence above, but your first term is one unit less)
d. -25; -75
(same thing as before, but now, <em>d</em> is negative)
e. 11.5; 16.5
(with <em>d</em>=1/2 or 0.5)
f. 6+1/2; 8+1/2
Use these to check your answers after applying the formula, but know that I calculated on the fly and didn't check these.
Answer:
116
Step-by-step explanation:
290% as a decimal is 2.9. "Of" means multiply. You can now multiply 2.9 by 40 to get the answer 116.
Step-by-step explanation:
the area of a triangle is always
baseline × height / 2
where baseline and height are perpendicular (with a 90° angle) to each other.
it does not matter, if the height is inside or outside of the triangle.
so, in our case the area is
4×5/2 = 2×5 = 10 units²
