# Could you repost answer explanation to CollegeBoard Test 3, Math 4.23? Specifically, is there a way to solve this if you don’t know the little trig ID about complementary angles?

Could you repost answer explanation to CollegeBoard Test 3, Math 4.23? Specifically, is there a way to solve this if you don’t know the little trig ID about complementary angles?

# In the equation below, the angle measures are in radians and a is a constant…

In the equation below, the angle measures are in radians and is a constant.

𝑠𝑖𝑛(𝜋/8)=𝑐𝑜𝑠(𝜋/𝑎)

Which of the following could be the value of ?

# For what value(s) of x, 0<x<pi/2, is sinx<cosx

For what value(s) of x, 0<x<pi/2, is sinx<cosx

# In a circle with center O, the length of radius OB is 5. If the length of chord CD is 8, and if line CD perpendicular to line OB, then sin angle OCD =

Start by drawing it! Note that OC = 5 and OD = 5 because both of those are also radii. Note also that because chord CD is perpendicular to OB, it’s bisected by OB. In other words, it’s split into 2 segments each measuring 4.   Things are really coming together! Because we know our Pythagorean (more…)

# In the xy-plane what is the slope of the line that passes through the origin and makes a 42° angle with the positive x-axis? A. 0.67 B. 0.74 C. 0.90 D. 1.11

Trigonometry does the trick here. Below is that line making a 42° angle with the positive x-axis. I’ve also drawn a dotted segment to make myself a neat little right triangle. Remember that slope is rise over run—how high the line climbs divided by how far it travels right. In this case, the dotted segment (more…)

# sin (90-x) = 12/13 what is the value of sin x?

Think of a 5-12-13 triangle (that’s one of the Pythagorean triples you should know). Say angle A measures x°, which would make angle C measure (90 – x)°. (I’m choosing those based on the fact that I already know that the sine of angle C will be 12/13.) Now that we’ve got it set up, all we (more…)

# Hi, I was wondering if you could explain to me how x + y= π/2, sin x = cos y. Thank you!

Hi, I was wondering if you could explain to me how x + y= π/2, sin x = cos y. Thank you!

# Test 4 Section 3 Number 17

Test 4 Section 3 Number 17

# Test 7 Section 4 #36

Test 7 Section 4 #36

# Test 5, Section 4, Question 20. How do you get to the answer?

Test 5, Section 4, Question 20. How do you get to the answer?

# Test 3 Section 3 #20

Test 3 Section 3 #20

# Test 1 Section 3 number 19. Thanks!

Test 1 Section 3 number 19. Thanks!

# It is given that sin A = K , where A is an angle measured in radians and (pi)< A < 3(pi)/2…

It is given that sin A = K , where A is an angle measured in radians and (pi)< A < 3(pi)/2 . If sin B = K which of the following could be the value of B ?
A) A – (pi)
B) (pi) + A
C) 2(pi) – A
D) 3(pi) – A

# Which of the following gives the length of chord DF in the figure above ?

Which of the following gives the length of chord DF in the figure above ?

A) 2cos(1.7)
B) 2sin(1.7)
C) 4cos(0.85)
D) 4sin(0.85)

# If cosA is not equal to 1, then sin^2A/(1-cosA) =

If cosA is not equal to 1, then sin^2A/ 1-cosA =

A) 1 + cosA
B) cosA
C) 1-cosA
D) 1
E) cosA -1