(sina cosb)×(sina-cosb)-(cos^2b-cos^2a)=0 prove it?
To prove the given equation, we need to simplify the expression on the left-hand side (LHS) and show that it is equal to zero.
Simplifying the LHS:
We start by expanding the expression using the trigonometric identities:
LHS = (sin a cos b) × (sin a - cos b) - (cos^2 b - cos^2 a)
Expanding the first term using the distributive property:
LHS = sin^2 a cos b - sin a cos^2 b - (cos^2 b - cos^2 a)
Using the identity sin^2 x = 1 - cos^2 x, we can rewrite the first term:
LHS = (1 - cos^2 a) cos b - sin a cos^2 b - (cos^2 b - cos^2 a)
Now, let's simplify each term separately:
Term 1: (1 - cos^2 a) cos b = cos b - cos^2 a cos b
Term 2: -sin a cos^2 b = -cos^2 b sin a
Term 3: -(cos^2 b - cos^2 a) = cos^2 a - cos^2 b
Substituting these simplified terms back into the original expression:
LHS = (cos b - cos^2 a cos b) - (cos^2 b sin a) - (cos^2 a - cos^2 b)
Now, let's combine like terms:
LHS = cos b - cos^2 a cos b - cos^2 b sin a - cos^2 a + cos^2 b
Rearranging the terms:
LHS = cos b - cos^2 a cos b - cos^2 a + cos^2 b - cos^2 b sin a
Simplifying further:
LHS = cos b - cos^2 a + cos^2 b - cos^2 a cos b - cos^2 b sin a
Now, let's factor out common terms:
LHS = (1 - cos^2 a) - cos^2 a cos b + (1 - cos^2 b) - cos^2 b sin a
Using the identity sin^2 x = 1 - cos^2 x again:
LHS = sin^2 a - cos^2 a cos b + sin^2 b - cos^2 b sin a
Simplifying:
LHS = sin^2 a + sin^2 b - cos a cos b (cos a + cos b)
Applying the identity sin^2 x + cos^2 x = 1:
LHS = 1 - cos a cos b (cos a + cos b)
Proving the Equation:
To prove that LHS = 0, we need to show that 1 - cos a cos b (cos a + cos b) = 0.
Let's consider two cases:
Case 1: If cos a = 0 or cos b = 0, then the equation is satisfied since any term multiplied by zero results in zero.
Case 2: If cos a and cos b are not zero, then we can divide both sides of the equation by cos a cos b (cos a + cos b):
1 - cos a cos b (cos a + cos b) = 0
Dividing by cos a cos
(sina cosb)×(sina-cosb)-(cos^2b-cos^2a)=0 prove it?
To prove the equation (sina cosb)×(sina-cosb)-(cos^2b-cos^2a) = 0, we can start by expanding the expression and simplifying it step by step.
Expanding the expression:
(sina cosb)×(sina-cosb)-(cos^2b-cos^2a)
Distributing sina cosb:
(sina^2 cosb - sina cos^2b) - (cos^2b - cos^2a)
Simplifying the expression:
sina^2 cosb - sina cos^2b - cos^2b + cos^2a
Grouping similar terms:
sina^2 cosb - sina cos^2b - (cos^2b - cos^2a)
Using the identity sin^2x + cos^2x = 1:
sina^2 cosb - sina cos^2b - (1 - cos^2a)
Expanding the brackets:
sina^2 cosb - sina cos^2b - 1 + cos^2a
Combining like terms:
sina^2 cosb - sina cos^2b + cos^2a - 1
Now, to prove that this expression is equal to 0, we need to show that it simplifies further to 0.
Using the identity sin^2x + cos^2x = 1:
(1 - cos^2b) cosb - sina cos^2b + cos^2a - 1
Expanding the brackets:
cosb - cos^3b - sina cos^2b + cos^2a - 1
Combining like terms:
cosb - cos^3b - sina cos^2b + cos^2a - 1
Rearranging the terms:
cosb - sina cos^2b + cos^2a - cos^3b - 1
Using the identity sin^2x + cos^2x = 1:
cosb - (1 - sin^2b) cos^2b + cos^2a - cos^3b - 1
Expanding the brackets:
cosb - cos^2b + sin^2b cos^2b + cos^2a - cos^3b - 1
Combining like terms:
cosb - cos^2b + sin^2b cos^2b + cos^2a - cos^3b - 1
Rearranging the terms:
cosb - cos^2b + sin^2b cos^2b - cos^3b + cos^2a - 1
Using the identity sin^2x + cos^2x = 1:
cosb - cos^2b + (1 - cos^2b) cos^2b - cos^3b + cos^2a - 1
Expanding the brackets:
cosb - cos^2b + cos^2b - cos^4b - cos^3b + cos^
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