# If (x 2 – y 2)sinx + (2xy)cosx = x 2 + y 2, then find the value of tan

| If (x

^{2}– y^{2})sinx + (2xy)cosx = x^{2}+ y^{2}, then find the value of tanx ?A.

B.

C.

D.

### Right Answer is: B

#### SOLUTION

If (x^{2} – y^{2})sinx + (2xy)cosx = x^{2} + y^{2}

Divided both side by x^{2} + y^{2}:

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⇒ ………….(1)

Let ∠C =

Hence (AC)^{2} = (AB)^{2} + (BC)^{2}

Also (x^{2} + y^{2})^{2 }= (2xy)^{2} + (x^{2} – y^{2})^{2}

Hence AC = x^{2} + y^{2}

AB = 2xy

BC = x^{2} – y^{2}

Hence ……………………(2)

………………….(3)

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If (x 2 – y 2)sinx + (2xy)cosx = x 2 + y 2, then find the value of tan