in any triangleABC P.T

(b²-c²)cotA + (c²-a²)cotB + (a²-b²)cotC = 0

Prove cos5x=16cos⁵x-20cos³x+5cosx

prove that cos11+sin11/cos11-sin11=tan56

prove using sine rule - 1) sin ( B-C)/2 = b-c/a cos ( A/2)

2)1+cos(A-B) cos C / 1+cos(A-C) cos B = a2+ b2/ a2- c2

3) (b-c)cot (A/2) + (c-a)cot (B/2) + (a-b)cot (C/2) = 0

4) a cos(B-C/2) = (b+c) sin(A/2)

5) c/(a-b) = tan(A/2) + tan(B/2) / tan(A/2) - tan(B/2)

6) a(cos C - cos B) = 2(b-c) cos^2 (A/2)

show that tan3x-tan2x-tanx =tan3x*tan2x*tanx

IF cos(alpha + beta) = 4/5 and sin(alpha - beta) = 5/13

FIND THE VALUE OF tan 2 alpha, where 0 is less than equal to alpha is less than equal to pie/4.

plz reply!!

 Prove that    tan4x= (4tanx(1-tan^2x)) / 1-6tan^x+tan^4x

a tree stands vertically on a hill side which makes an angle of 15degree with the horizontal. from a point on the ground 35m down the hill from the base of the tree, the angle of elevation of the top of the tree is 60degree. find the height of the tree.

ans(35root2m) plese tell the xact solution

prove-

cos²(pi /8) + cos^{2 (}3pi / 8) +cos²(5pi / 8) +cos^{2 (}7pi / 8) = 2

Solve the equation:

4sinxcosx + 2sinx + 2cosx + 1 = 0

Show that cos 24 + cos 55 + cos 125 + cos 204 + cos 300= 1/2

If A+B+C = pai, prove that

sinA + sinB + sinC = 4 cosA/2 cosB/2 cosC/2

find the derivative of cotx by the first principle?

The angles of a triangle are in AP and the ratio of the number of degrees in the least to the number of radians in the greatest is 60:π. Find the angles in degrees and radians.

prove sin²A - sin²B/sinA .cosA- sinB. cosB = tan(A+B)