TRIGONOMETRICAL IDENTITIES - PART – 100

134. sin A cos A – 
[sin A cos (  – A) cos A / sec (  – A)] - 
[cos A sin (  – A) sin A / cosec (  – A)] = 0

TRIGONOMETRICAL IDENTITIES - PART – 99

133. cosec Ꝋ - sin Ꝋ = m, sec Ꝋ - cos Ꝋ = n

Show that (m²n)^2/3 + (mn²)^2/3 = 1

TRIGONOMETRICAL IDENTITIES - PART – 98

132. Prove that :

sin A / sin (90 – A) + cos / cos (90 – A)

=

sec A cosec A

TRIGONOMETRICAL IDENTITIES - PART – 97

131. Solve for x, 0 ≤ x ≤ 90ﹾ

(i) 3 tan² 2x = 1

(ii) tan² x = 3 (sec x – 1)

TRIGONOMETRICAL IDENTITIES - PART – 96

130. Solve for x, 0 ≤ x ≤ 90ﹾ

(i) 4 cos²2x – 3  = 0

(ii) 2 sin²x – sin x  = 0

TRIGONOMETRICAL IDENTITIES - PART – 95

129. If cos A = 9/ 41; find the value of

(1 / sin² A) –  (1 / tan² A)

TRIGONOMETRICAL IDENTITIES - PART – 94

128. If (2 cos 2 A – 1) (tan 3 A – 1) = 0; find the  values of A.   

TRIGONOMETRICAL IDENTITIES - PART – 93

127. If tan A = 1 and tan B = √3; evaluate

(i) cos A cos B – sin A sin B

(ii) sin A cos B + cos A sin B

TRIGONOMETRICAL IDENTITIES - PART – 92

126. Find   ; find A, if :

(i) sin A / (sec A – 1) + sin A / (sec A – 1) = 2      

TRIGONOMETRICAL IDENTITIES - PART – 91

125. Find   ; find A, if :

(i) cos A / (1 – sin A) + cos A / (1 + sin A) = 4

TRIGONOMETRICAL IDENTITIES - PART – 90

Find A, if A is less than zero and A is less than 90 degrees.

(1) cos² A – cos A = 0

(2) 2 cos² A + cos A – 1 = 0

TRIGONOMETRICAL IDENTITIES - PART – 89

Find A, if A is less then are equal to zero and A is greater than are equal to zero.

(1) 2 cos² A – 1 = 0 , (2) sin 3 A – 1 = 0 and 

(3) 4 sin² A – 3 = 0