Trigonometry Answers

what is the x-intercept of f(x)=2/5-3?

Model equation for tide: h=2 cos⁡(π/6 t-2π/3)+4
Given the above, a large boat needs at least 4 meters of water to secure it at the end of the pier. Determine what span of time after noon, including both a starting and ending time, the boat can first safely be secured, justifying your answer.
So far, I have gotten this, but I'm stuck!
4=2 cos⁡(π/6 t-2π/3)+4
0=2 cos⁡(π/6 t-2π/3)
0=cos⁡(π/6 t-2π/3)
0=cos⁡(π/6 t) cos⁡(2π/3)+sin⁡(π/6 t) sin⁡(2π/3)

Am I even remotely on the right track??? Can someone PLEASE help?!?

Prove that in a triangle with angles A, B and C; and sides of length a, b and c that:

1/[(a-b)(a-c)]*tan(A/2) + 1/[(b-c)(b-a)]*tan(B/2) + 1/[(c-b)(c-a)]*tan(C/2) =(Area of triangle)^(-1)

{NOTE: 'a' is the length of side opposite to angle A, likewise 'b' is the length of side opposite to angle B and similarly 'c' is the length of side opposite to angle C.}

• How can a trigonometric function be chosen to model periodic phenomena with specified amplitude, frequency, and midline?

Find the area of the triangle with the given measurements. Round the solution to the nearest hundredth if necessary.

A = 46°, b = 27 ft, c = 14 ft

why sin(a+b)is not equal to sin a+sin b

Write an equation in slope-intercept form for the line with slope -3and y-intercept-2 .

THS IS FUNCTIONS (CHAPTER ;RELATION BETWEEN SIDES AND ANGle or using sine formula show that each of the following holdand the law of sine rule

Q1 .tan A-B/2/TAN A+B/2=a-b/a+b
Q2 .b cos B+c cos C=a cos (B-C)
Q3 a sin B-C/2\=(b-c) cos A/2
Q4 b+c/b-c=tan B+C/2 * COT B-C/2
Q5 a cosA+b cos C+c cos C=2a sinB sinC
Q5. IN ANY TRIANGLE IF a/ cosA=b/cosB, PROVE THAT THE TRIANGLE IS ISOSCELES

A plane flew 150 miles on a course of 2200 and then 130 miles on a course 1300. Then the plane returned to its starting point via the shortest route possible. Find that shortest distance.

tan⁡θ= (sin⁡α-cos⁡α)/(sin⁡α+cos⁡α ) ,then sin⁡α+cos⁡α = ?