Question

If \(\sin\theta-\cos\theta=\frac{4}{5}\), then the value of \(\sin\theta+\cos\theta=\)

• A. \(\frac{5}{\sqrt{34}}\)
• B. \(-\frac{5}{\sqrt{34}}\)
• C. \(-\frac{\sqrt{34}}{25}\)
• D. \(\frac{\sqrt{34}}{5}\)

Hint:

Use \((\sin\theta+\cos\theta)^2\) and \((\sin\theta-\cos\theta)^2\). Their difference depends on \(2\sin\theta\cos\theta\).

Answer 1

The Correct Option is D